ICSE – Grade 10 – Chemistry – Ch 12 – QA

Questions & Answers

ICSE - Grade - 10

Subject: Chemistry

Chapter - 12 - Organic Chemistry

Types of Questions

MCQ

  1. Which of the following is a saturated hydrocarbon?
     a) C₂H₄
     b) C₃H₆
     c) C₄H₁₀
     d) C₂H₂
     Answer: c) C₄H₁₀


  2. What is the general formula of alkanes?
     a) CₙH₂ₙ
     b) CₙH₂ₙ₊₂
     c) CₙH₂ₙ₋₂
     d) CₙH₂ₙ₋₆
     Answer: b) CₙH₂ₙ₊₂


  3. Which compound represents an alkene?
     a) C₂H₆
     b) C₂H₄
     c) C₂H₂
     d) C₃H₈
     Answer: b) C₂H₄


  4. Ethyne is also known as:
     a) Ethylene
     b) Acetylene
     c) Ethane
     d) Ethanol
     Answer: b) Acetylene


  5. The functional group in alcohols is:
     a) –COOH
     b) –OH
     c) –CHO
     d) –CO
     Answer: b) –OH


  6. The molecular formula of propanol is:
     a) C₃H₈O
     b) C₃H₆O
     c) C₃H₆
     d) C₃H₄O
     Answer: a) C₃H₈O


  7. Which of the following compounds is a carboxylic acid?
     a) CH₃OH
     b) CH₃COOH
     c) C₂H₄
     d) C₂H₂
     Answer: b) CH₃COOH


  8. The process of converting an alkene to an alkane by adding hydrogen is called:
     a) Hydration
     b) Hydrogenation
     c) Halogenation
     d) Dehydration
     Answer: b) Hydrogenation


  9. Ethene undergoes addition reaction with:
     a) Bromine water
     b) Sodium hydroxide
     c) Ammonia
     d) Water only
     Answer: a) Bromine water


  10. The formula of butyne is:
     a) C₄H₈
     b) C₄H₆
     c) C₄H₁₀
     d) C₄H₄
     Answer: b) C₄H₆


  11. Which of the following is not true about alkanes?
     a) They are saturated hydrocarbons
     b) They contain only single bonds
     c) They undergo addition reactions easily
     d) They are generally less reactive
     Answer: c) They undergo addition reactions easily


  12. Which reagent is used to test the presence of unsaturation in hydrocarbons?
     a) Acidified potassium permanganate
     b) Sodium chloride
     c) Hydrochloric acid
     d) Sulfuric acid
     Answer: a) Acidified potassium permanganate


  13. The reaction of alcohols with sodium metal produces:
     a) Alcoholate and hydrogen gas
     b) Sodium hydroxide
     c) Ester and water
     d) Carboxylic acid
     Answer: a) Alcoholate and hydrogen gas


  14. Which of the following is the correct IUPAC name for CH₃CH₂OH?
     a) Methanol
     b) Ethanol
     c) Propanol
     d) Ethene
     Answer: b) Ethanol


  15. Ethanoic acid has the molecular formula:
     a) C₂H₄O₂
     b) C₂H₆O
     c) C₂H₂O
     d) C₂H₄O
     Answer: a) C₂H₄O₂


  16. What type of bond is present between carbon atoms in an alkyne?
     a) Single bond
     b) Double bond
     c) Triple bond
     d) No bond
     Answer: c) Triple bond


  17. Which is the most reactive among alkanes, alkenes, and alkynes?
     a) Alkanes
     b) Alkenes
     c) Alkynes
     d) All equally reactive
     Answer: c) Alkynes


  18. The boiling point of alcohols is generally higher than that of alkanes due to:
     a) Hydrogen bonding
     b) Van der Waals forces
     c) Ionic bonding
     d) Covalent bonding
     Answer: a) Hydrogen bonding


  19. The major product formed when ethene reacts with water in presence of acid is:
     a) Ethanol
     b) Ethane
     c) Ethyne
     d) Ethanoic acid
     Answer: a) Ethanol


  20. Which of the following is not an alkane?
     a) Methane
     b) Ethyne
     c) Propane
     d) Butane
     Answer: b) Ethyne


  21. The homologous series that contains a carbon-carbon double bond is called:
     a) Alkane
     b) Alkene
     c) Alkyne
     d) Alcohol
     Answer: b) Alkene


  22. Carboxylic acids have which functional group?
     a) –OH
     b) –COOH
     c) –CHO
     d) –NH₂
     Answer: b) –COOH


  23. The reaction of ethanol with sodium metal produces:
     a) Sodium ethoxide and hydrogen gas
     b) Sodium hydroxide and water
     c) Sodium acetate and hydrogen gas
     d) Ethene and water
     Answer: a) Sodium ethoxide and hydrogen gas


  24. What is the main type of reaction undergone by alkenes?
     a) Substitution
     b) Addition
     c) Elimination
     d) Combustion
     Answer: b) Addition


  25. Which gas is released when carboxylic acid reacts with a metal carbonate?
     a) Oxygen
     b) Carbon dioxide
     c) Hydrogen
     d) Nitrogen
     Answer: b) Carbon dioxide


  26. The IUPAC name of CH₃CH=CH₂ is:
     a) Ethene
     b) Propene
     c) Propane
     d) Propyne
     Answer: b) Propene


  27. Alkynes are characterized by:
     a) Single bonds between carbon atoms
     b) Double bonds between carbon atoms
     c) Triple bonds between carbon atoms
     d) No bonds between carbon atoms
     Answer: c) Triple bonds between carbon atoms


  28. Which of the following alcohols is a primary alcohol?
     a) Methanol
     b) Isopropanol
     c) Tertiary butanol
     d) None of these
     Answer: a) Methanol


  29. The common name of ethanoic acid is:
     a) Acetic acid
     b) Formic acid
     c) Citric acid
     d) Lactic acid
     Answer: a) Acetic acid


  30. The test for unsaturation involves:
     a) Decolourization of bromine water
     b) Formation of precipitate with silver nitrate
     c) Evolution of hydrogen gas with sodium metal
     d) Neutralization with sodium hydroxide
     Answer: a) Decolourization of bromine water


  31. The product of complete combustion of alkanes is:
     a) CO and H₂O
     b) CO₂ and H₂O
     c) CO and CO₂
     d) C and H₂O
     Answer: b) CO₂ and H₂O


  32. Which is an example of a tertiary alcohol?
     a) CH₃CH₂OH
     b) (CH₃)₃COH
     c) CH₃CHOHCH₃
     d) CH₃OH
     Answer: b) (CH₃)₃COH


  33. Which of the following is a product of esterification?
     a) Alcohol and water
     b) Ester and water
     c) Alcohol and acid
     d) Acid and salt
     Answer: b) Ester and water


  34. Which of these compounds will undergo electrophilic addition reactions?
     a) Alkane
     b) Alkene
     c) Alkyne
     d) Both b and c
     Answer: d) Both b and c


  35. Which reagent converts ethanol to ethene?
     a) Concentrated sulfuric acid and heat
     b) Bromine water
     c) Sodium metal
     d) Potassium permanganate
     Answer: a) Concentrated sulfuric acid and heat


  36. Which of the following hydrocarbons is unsaturated?
     a) Methane
     b) Ethyne
     c) Propane
     d) Butane
     Answer: b) Ethyne


  37. The IUPAC name of CH≡CH is:
     a) Ethene
     b) Ethyne
     c) Ethane
     d) Methyne
     Answer: b) Ethyne


  38. Which of the following is true about carboxylic acids?
     a) They have a sharp smell
     b) They are weak acids
     c) They react with metals to produce hydrogen gas
     d) All of the above
     Answer: d) All of the above


  39. The functional group in aldehydes is:
     a) –OH
     b) –CHO
     c) –COOH
     d) –CO
     Answer: b) –CHO


  40. Ethylene glycol is an example of:
     a) Monohydric alcohol
     b) Dihydric alcohol
     c) Trihydric alcohol
     d) None of these
     Answer: b) Dihydric alcohol


  41. The molecular formula of ethyne is:
     a) C₂H₂
     b) C₂H₄
     c) C₂H₆
     d) C₃H₄
     Answer: a) C₂H₂


  42. Which compound is formed by partial oxidation of alcohol?
     a) Aldehyde
     b) Ketone
     c) Carboxylic acid
     d) Alkane
     Answer: a) Aldehyde


  43. Which of the following compounds will undergo substitution reaction?
     a) Alkane
     b) Alkene
     c) Alkyne
     d) Alcohol
     Answer: a) Alkane


  44. In alcohol, the –OH group is attached to:
     a) Carbon atom
     b) Hydrogen atom
     c) Oxygen atom
     d) Nitrogen atom
     Answer: a) Carbon atom


  45. The acid present in vinegar is:
     a) Methanoic acid
     b) Ethanoic acid
     c) Propanoic acid
     d) Butanoic acid
     Answer: b) Ethanoic acid


  46. Which one is a saturated hydrocarbon?
     a) Ethyne
     b) Ethene
     c) Ethane
     d) Ethanol
     Answer: c) Ethane


  47. The type of reaction in which an alkene reacts with hydrogen halide is:
     a) Addition
     b) Substitution
     c) Elimination
     d) Combustion
     Answer: a) Addition


  48. Alcohols can be prepared by:
     a) Hydration of alkenes
     b) Halogenation of alkanes
     c) Combustion of hydrocarbons
     d) Dehydration of alkanes
     Answer: a) Hydration of alkenes


  49. The simplest alkyne is:
     a) Methyne
     b) Ethyne
     c) Propyne
     d) Butyne
     Answer: b) Ethyne


  50. Which of the following is formed by the fermentation of sugars?
     a) Ethanol
     b) Methanol
     c) Propanol
     d) Ethene
     Answer: a) Ethanol

Fill in the Blanks

  1. The general formula of alkanes is __________.
     Answer: CₙH₂ₙ₊₂


  2. Ethene is an example of an __________ hydrocarbon.
     Answer: unsaturated


  3. The functional group of alcohols is __________.
     Answer: –OH


  4. The simplest alkyne is __________.
     Answer: ethyne (C₂H₂)


  5. The IUPAC name of CH₃CH₂OH is __________.
     Answer: ethanol


  6. Carboxylic acids contain the __________ functional group.
     Answer: –COOH


  7. The molecular formula of methane is __________.
     Answer: CH₄


  8. Alkanes contain only __________ bonds between carbon atoms.
     Answer: single


  9. Bromine water is used to test for __________ in hydrocarbons.
     Answer: unsaturation


  10. The process of adding hydrogen to an alkene is called __________.
     Answer: hydrogenation


  11. Ethyne is commonly known as __________.
     Answer: acetylene


  12. The boiling points of alcohols are higher than alkanes due to __________ bonding.
     Answer: hydrogen


  13. The molecular formula of propanol is __________.
     Answer: C₃H₈O


  14. The reaction between a carboxylic acid and an alcohol produces an __________.
     Answer: ester


  15. The homologous series with the general formula CₙH₂ₙ is __________.
     Answer: alkenes


  16. The IUPAC name of CH₃CH=CH₂ is __________.
     Answer: propene


  17. Alkynes contain a __________ bond between carbon atoms.
     Answer: triple


  18. Methanol is a __________ alcohol.
     Answer: primary


  19. The gas released when carboxylic acid reacts with metal carbonates is __________.
     Answer: carbon dioxide


  20. The molecular formula of ethanoic acid is __________.
     Answer: C₂H₄O₂


  21. When ethanol reacts with sodium metal, it produces sodium __________ and hydrogen gas.
     Answer: ethoxide


  22. The product of complete combustion of alkanes is carbon dioxide and __________.
     Answer: water


  23. The test for unsaturation results in the __________ of bromine water.
     Answer: decolourisation


  24. Ethanol is produced by the __________ of sugars.
     Answer: fermentation


  25. The IUPAC name of CH≡CH is __________.
     Answer: ethyne


  26. Alkanes are __________ hydrocarbons.
     Answer: saturated


  27. The reaction of an alkene with water in presence of acid is called __________.
     Answer: hydration


  28. The molecular formula of butyne is __________.
     Answer: C₄H₆


  29. Alcohols react with sodium metal to produce __________ gas.
     Answer: hydrogen


  30. The carbon-carbon double bond in alkenes makes them more __________ than alkanes.
     Answer: reactive


  31. The IUPAC name of CH₃COOH is __________.
     Answer: ethanoic acid


  32. The general formula of alkynes is __________.
     Answer: CₙH₂ₙ₋₂


  33. The process of removing water from alcohol to form alkene is called __________.
     Answer: dehydration


  34. The functional group –CHO represents __________.
     Answer: aldehyde


  35. Propane is an example of an __________.
     Answer: alkane


  36. Ethylene glycol is a __________ alcohol.
     Answer: dihydric


  37. Alkanes do not readily undergo __________ reactions.
     Answer: addition


  38. The functional group of carboxylic acids contains __________ and hydroxyl groups.
     Answer: carbonyl


  39. The IUPAC name for CH₃CH₂CH₂OH is __________.
     Answer: propanol


  40. The reaction in which hydrogen halide adds to an alkene is called __________.
     Answer: addition


  41. The molecular formula of methane is __________.
     Answer: CH₄


  42. The hydrocarbon C₂H₆ is called __________.
     Answer: ethane


  43. Alcohols can be prepared by __________ of alkenes.
     Answer: hydration


  44. The common name of ethanoic acid is __________ acid.
     Answer: acetic


  45. Alkynes have __________ bonds between carbon atoms.
     Answer: triple


  46. The IUPAC name of (CH₃)₃COH is __________ alcohol.
     Answer: tertiary butanol


  47. The process of converting an alkene into an alkane is called __________.
     Answer: hydrogenation


  48. The molecular formula of butane is __________.
     Answer: C₄H₁₀


  49. Ethanol has __________ carbon atom(s).
     Answer: two


  50. The reaction between carboxylic acid and metal produces __________ gas.
     Answer: hydrogen

Name the Following

  1. CH₄
     Answer: Methane


  2. C₂H₆
     Answer: Ethane


  3. C₃H₈
     Answer: Propane


  4. C₄H₁₀
     Answer: Butane


  5. C₂H₄
     Answer: Ethene


  6. C₃H₆
     Answer: Propene


  7. C₄H₈
     Answer: Butene


  8. C₂H₂
     Answer: Ethyne


  9. C₃H₄
     Answer: Propyne


  10. C₄H₆
     Answer: Butyne


  11. CH₃OH
     Answer: Methanol


  12. C₂H₅OH
     Answer: Ethanol


  13. C₃H₇OH (1-Propanol)
     Answer: Propanol


  14. C₃H₇OH (2-Propanol)
     Answer: Isopropanol (2-Propanol)


  15. C₄H₉OH
     Answer: Butanol


  16. CH₃COOH
     Answer: Ethanoic acid (Acetic acid)


  17. HCOOH
     Answer: Methanoic acid (Formic acid)


  18. C₂H₅COOH
     Answer: Propanoic acid


  19. C₃H₇COOH
     Answer: Butanoic acid


  20. CH₃CH₂CH=CH₂
     Answer: Butene


  21. CH₃CH=CH₂
     Answer: Propene


  22. CH≡CH
     Answer: Ethyne (Acetylene)


  23. CH₃CH₂CH₂OH
     Answer: 1-Propanol


  24. (CH₃)₂CHOH
     Answer: Isopropanol (2-Propanol)


  25. (CH₃)₃COH
     Answer: Tertiary butanol


  26. C₂H₅Cl
     Answer: Chloroethane


  27. CH₃CH₂Br
     Answer: Bromoethane


  28. C₆H₆
     Answer: Benzene


  29. C₆H₁₂
     Answer: Cyclohexane


  30. CH₃CH₂CH₂Br
     Answer: 1-Bromopropane


  31. CH₃CHO
     Answer: Ethanal (Acetaldehyde)


  32. CH₃CH₂CHO
     Answer: Propanal


  33. CH₃CH₂COOH
     Answer: Propanoic acid


  34. C₄H₈
     Answer: Butene


  35. C₃H₄
     Answer: Propyne


  36. CH₃CH₂CH₂CH₂OH
     Answer: 1-Butanol


  37. CH₃CH₂CH₂COOH
     Answer: Butanoic acid


  38. C₂H₄Cl₂
     Answer: 1,2-Dichloroethane


  39. C₄H₁₀O
     Answer: Butanol (any isomer)


  40. CH₃CH₂OCH₃
     Answer: Ethyl methyl ether


  41. C₆H₅OH
     Answer: Phenol


  42. CH₃COCH₃
     Answer: Acetone (Propanone)


  43. C₂H₄Br₂
     Answer: 1,2-Dibromoethane


  44. CH₃CH₂CH=CH₂
     Answer: 1-Butene


  45. C₄H₆
     Answer: Butyne


  46. CH₃CH₂CH₂CH₂COOH
     Answer: Pentanoic acid


  47. CH₃CH=CHCH₃
     Answer: 2-Butene


  48. CH₃CH₂C≡CH
     Answer: 1-Butyne


  49. CH₃CH₂OH
     Answer: Ethanol


  50. CH₃CH₂COOH
     Answer: Propanoic acid

Answer in One Word

  1. The general formula of alkanes.
     Answer: CₙH₂ₙ₊₂


  2. Functional group in alcohols.
     Answer: Hydroxyl


  3. Simplest alkyne.
     Answer: Ethyne


  4. Process of adding hydrogen to alkenes.
     Answer: Hydrogenation


  5. The product when carboxylic acid reacts with metal carbonate.
     Answer: Carbon dioxide


  6. IUPAC name of CH₄.
     Answer: Methane


  7. Test for unsaturation in hydrocarbons.
     Answer: Bromine


  8. Functional group of carboxylic acid.
     Answer: Carboxyl


  9. Gas released when alcohol reacts with sodium metal.
     Answer: Hydrogen


  10. Type of hydrocarbon with single bonds only.
     Answer: Alkane


  11. IUPAC name of C₂H₄.
     Answer: Ethene


  12. Reaction where water adds to an alkene.
     Answer: Hydration


  13. Alkene with three carbon atoms.
     Answer: Propene


  14. Functional group in aldehydes.
     Answer: Aldehyde


  15. Name for C₂H₂.
     Answer: Ethyne


  16. Type of bond in alkynes.
     Answer: Triple


  17. Alcohol with two –OH groups.
     Answer: Dihydric


  18. General formula of alkenes.
     Answer: CₙH₂ₙ


  19. Alcohol used in alcoholic beverages.
     Answer: Ethanol


  20. Reaction to remove water from alcohol.
     Answer: Dehydration


  21. The compound CH₃COOH is called __________ acid.
     Answer: Acetic


  22. Gas released when carboxylic acid reacts with metal.
     Answer: Hydrogen


  23. The IUPAC name of CH₃CH₂OH.
     Answer: Ethanol


  24. A saturated hydrocarbon.
     Answer: Alkane


  25. The IUPAC name of CH₃CH=CH₂.
     Answer: Propene


  26. Homologous series with triple bond.
     Answer: Alkyne


  27. The IUPAC name of CH₃CH₂CH₂OH.
     Answer: Propanol


  28. The name of functional group –OH.
     Answer: Hydroxyl


  29. The reaction of an alkene with hydrogen halide is called __________.
     Answer: Addition


  30. Alkane with four carbon atoms.
     Answer: Butane


  31. The product of complete combustion of hydrocarbons.
     Answer: Carbon dioxide


  32. The IUPAC name for CH₃CH₂COOH.
     Answer: Propanoic acid


  33. Hydrocarbon with double bonds.
     Answer: Alkene


  34. The compound C₃H₄ is called __________.
     Answer: Propyne


  35. Functional group of esters.
     Answer: Ester


  36. The simplest alcohol.
     Answer: Methanol


  37. Alkene with four carbon atoms.
     Answer: Butene


  38. The reaction to form alcohol from alkene is called __________.
     Answer: Hydration


  39. Gas given off when alcohol reacts with metals.
     Answer: Hydrogen


  40. Functional group –COOH is called __________.
     Answer: Carboxyl


  41. Compound with formula C₆H₆.
     Answer: Benzene


  42. Reaction where alkene reacts with bromine.
     Answer: Addition


  43. Alcohol with three carbon atoms and hydroxyl group on the second carbon.
     Answer: Isopropanol


  44. Alkyne with four carbon atoms.
     Answer: Butyne


  45. The test that decolorizes bromine water.
     Answer: Unsaturation


  46. The process of fermentation produces __________.
     Answer: Ethanol


  47. Compound CH₃CH₂Cl is called __________.
     Answer: Chloroethane


  48. The functional group of ketones.
     Answer: Carbonyl


  49. Alkane with three carbon atoms.
     Answer: Propane


  50. Compound CH₃OH is called __________.
     Answer: Methanol

ICSE - Grade 10 - Physics

All Chapters

  • Chapter 1 – Force
  • Chapter 2 – Work, Energy and Power
  • Chapter 3 – Machines
  • Chapter 4 – Refraction of Light at Plane Surfaces
  • Chapter 5 – Refraction through Lens
  • Chapter 6 – Spectrum
  • Chapter 7 – Sound
  • Chapter 8 – Current Electricity
  • Chapter 9 – Electrical Power and Household Circuits
  • Chapter 10 – Electro-magnetism
  • Chapter 11 – Calorimetry
  • Chapter 12 – Radioactivity

ICSE - Grade 10 - Chemistry

All Chapters

  • Chapter 1 The Language of Chemistry
  • Chapter 2 Chemical Changes and Reactions
  • Chapter 3 Water
  • Chapter 4 Atomic Structure and Chemical Bonding
  • Chapter 5 The periodic table
  • Chapter 6 Study of the first Element Hydrogen
  • Chapter 7 Study of Gas laws
  • Chapter 8 Atmospheric Pollution

ICSE - Grade 10 - Mathematics

All Chapters

  • Chapter 1 Rational and Irrational Numbers
  • Chapter 2 Compound Interest [Without Using Formula]
  • Chapter 3 Compound Interest [Using Formula]
  • Chapter 4 Expansions
  • Chapter 5 Factorisation
  • Chapter 6 Simultaneous Equations
  • Chapter 7 Indices
  • Chapter 8 Logarithms
  • Chapter 9 Triangles
  • Chapter 10 Isosceles Triangles
  • Chapter 11 Inequalities
  • Chapter 12 Midpoint and Its Converse
  • Chapter 13 Pythagoras Theorem
  • Chapter 14 Rectilinear Figures
  • Chapter 15 Construction of Polygons
  • Chapter 16 Area Theorems
  • Chapter 17 Circle
  • Chapter 18 Statistics
  • Chapter 19 Mean and Median
  • Chapter 20 Area and Perimeter of Plane Figures
  • Chapter 21 Solids
  • Chapter 22 Trigonometrical Ratios
  • Chapter 23 Trigonometrical Ratios of Standard Angles
  • Chapter 24 Solutions of Right Triangles
  • Chapter 25 Complementary Angles
  • Chapter 26 Coordinate Geometry
  • Chapter 27 Graphical Solution
  • Chapter 28 Distance Formula

ICSE - Grade 10 - Biology

All Chapters

  • Chapter 1 Introducing Biology
  • Chapter 2 Cell: The Unit Of Life
  • Chapter 3 Tissues: Plant And Animal Tissue
  • Chapter 4 The Flower
  • Chapter 5 Pollination and Fertilization
  • Chapter 6 Seeds: Structure and Germination
  • Chapter 7 Respiration in Plants
  • Chapter 8 Five Kingdom Classification
  • Chapter 9 Economic Importance of Bacteria and Fungi
  • Chapter 10 Nutrition
  • Chapter 11 Digestive system
  • Chapter 12 Skeleton: Movement and Locomotion
  • Chapter 13 Skin: The Jack of all trades
  • Chapter 14 The Respiratory System
  • Chapter 15 Hygiene: [A key to Healthy Life]
  • Chapter 16 Diseases: Cause and Control
  • Chapter 17 Aids to Health
  • Chapter 18 Health Organizations
  • Chapter 19 Waste Generation and Management

ICSE - Grade 10 - History

All Chapters

  • Chapter 1 – The Harappan Civilisation
  • Chapter 2 – The Vedic Period
  • Chapter 3 – Jainism and Buddhism
  • Chapter 4 – The Mauryan Empire
  • History — Chapter 5
    The Sangam Age
  • Chapter 6 – The Age of the Guptas
  • Chapter 7 – Medieval India — (A) The Cholas
  • Chapter 8 – Medieval India — (B) The Delhi Sultanate
  • Chapter 9 – Medieval India — (C) The Mughal Empire
  • Chapter 10 – Medieval India — (D) Composite Culture
  • Chapter 11 – The Modern Age in Europe — (A) Renaissance
  • Chapter 12 – The Modern Age in Europe — (B) Reformation
  • Chapter 13 – The Modern Age in Europe — (C) Industrial Revolution
  •  

ICSE - Grade 10 - Civics

All Chapters

  • Chapter 1: Our Constitution
  • Chapter 2: Salient Features of the Constitution — I
  • Chapter 3: Salient Features of the
  • Constitution — II
  • Chapter 4: Elections
  • Chapter 5: Local Self-Government — Rural
  • Chapter 6: Local Self-Government — Urban
  •  

ICSE - Grade 10 - Geography

All Chapters

  • Ch 1 – Earth as a Planet
    Ch 2 – Geographic Grid: Latitudes and Longitudes
    Ch 3 – Rotation and Revolution
    Ch 4 – Earth’s Structure
    Ch 5 – Landforms of the Earth
    Ch 6 – Rocks
    Ch 7 – Volcanoes
    Ch 8 – Earthquakes
    Ch 9 – Weathering
    Ch 10 – Denudation
    Ch 11 – Hydrosphere
    Ch 12 – Composition and Structure of the Atmosphere
    Ch 13 – Insolation
    Ch 14 – Atmospheric Pressure and Winds
    Ch 15 – Humidity
    Ch 16 – Pollution
    Ch 17 – Sources of Pollution
    Ch 18 – Effects of Pollution
    Ch 19 – Preventive Measures
    Ch 20 – Natural Regions of the World

ICSE Grade 10

3500/-
  • All Subjects
  • Free Study Material
  • MCQ Tests
  • Theory Tests
  • Assignments
Register

Find the Odd Man Out

  1. Methane, Ethane, Ethene, Propane
     Answer: Ethene
     Explanation: Ethene is unsaturated (contains double bond); others are alkanes (saturated).


  2. Ethyne, Ethene, Propene, Butane
     Answer: Butane
     Explanation: Butane is an alkane; others are unsaturated hydrocarbons.


  3. Methanol, Ethanol, Ethyne, Propanol
     Answer: Ethyne
     Explanation: Ethyne is an alkyne; others are alcohols.


  4. Methane, Propane, Butyne, Ethane
     Answer: Butyne
     Explanation: Butyne contains a triple bond; others are alkanes.


  5. Ethanoic acid, Methanoic acid, Ethanol, Propanoic acid
     Answer: Ethanol
     Explanation: Ethanol is an alcohol; others are carboxylic acids.


  6. CH₄, C₂H₄, C₃H₈, C₄H₁₀
     Answer: C₂H₄
     Explanation: C₂H₄ (ethene) is an alkene; others are alkanes.


  7. Ethanol, Methanol, Propene, Butanol
     Answer: Propene
     Explanation: Propene is an alkene; others are alcohols.


  8. Butane, Butene, Butyne, Butanol
     Answer: Butanol
     Explanation: Butanol is an alcohol; others are hydrocarbons.


  9. Methane, Ethane, Propene, Propane
     Answer: Propene
     Explanation: Propene is unsaturated; others are saturated hydrocarbons.


  10. Ethene, Propene, Butyne, Methane
     Answer: Methane
     Explanation: Methane is an alkane; others are unsaturated hydrocarbons.


  11. Methanol, Ethanol, Acetone, Propanol
     Answer: Acetone
     Explanation: Acetone is a ketone; others are alcohols.


  12. CH₃COOH, HCOOH, C₂H₅OH, CH₃CH₂COOH
     Answer: C₂H₅OH
     Explanation: C₂H₅OH is an alcohol; others are carboxylic acids.


  13. CH₄, C₂H₆, C₃H₈, C₃H₆
     Answer: C₃H₆
     Explanation: C₃H₆ (propene) is an alkene; others are alkanes.


  14. C₂H₂, C₂H₄, C₂H₆, C₃H₈
     Answer: C₂H₂
     Explanation: C₂H₂ (ethyne) contains a triple bond; others have single or double bonds.


  15. Ethene, Ethyne, Ethane, Propane
     Answer: Ethane
     Explanation: Ethane is saturated alkane; others are unsaturated hydrocarbons.


  16. Methane, Methanol, Ethanol, Propanol
     Answer: Methane
     Explanation: Methane is hydrocarbon; others are alcohols.


  17. Ethanoic acid, Methanoic acid, Propanoic acid, Butane
     Answer: Butane
     Explanation: Butane is alkane; others are carboxylic acids.


  18. Propane, Propene, Propyne, Propanol
     Answer: Propanol
     Explanation: Propanol is an alcohol; others are hydrocarbons.


  19. Ethene, Propane, Ethyne, Butyne
     Answer: Propane
     Explanation: Propane is alkane; others are unsaturated hydrocarbons.


  20. Methanol, Ethanol, Methanal, Propanol
     Answer: Methanal
     Explanation: Methanal is an aldehyde; others are alcohols.


  21. CH₃CH₂OH, CH₃OH, C₂H₄, CH₄
     Answer: C₂H₄
     Explanation: C₂H₄ is alkene; others are alcohol or alkane.


  22. CH₃COOH, HCOOH, CH₃CH₂OH, C₂H₅COOH
     Answer: CH₃CH₂OH
     Explanation: CH₃CH₂OH is alcohol; others are carboxylic acids.


  23. C₂H₂, C₂H₄, C₂H₆, CH₄
     Answer: C₂H₂
     Explanation: C₂H₂ has triple bond; others do not.


  24. Ethanol, Methanol, Ethene, Propanol
     Answer: Ethene
     Explanation: Ethene is alkene; others are alcohols.


  25. Methane, Ethene, Propene, Butane
     Answer: Butane
     Explanation: Butane is alkane; others include alkenes.


  26. Ethanol, Propanol, Butane, Methanol
     Answer: Butane
     Explanation: Butane is alkane; others are alcohols.


  27. C₂H₅OH, CH₃OH, C₃H₆, C₄H₁₀
     Answer: C₃H₆
     Explanation: C₃H₆ is alkene; others are alcohol or alkane.


  28. Methane, Ethane, Ethyne, Propane
     Answer: Ethyne
     Explanation: Ethyne contains triple bond; others do not.


  29. CH₄, C₂H₆, C₃H₈, CH₃OH
     Answer: CH₃OH
     Explanation: CH₃OH is alcohol; others are hydrocarbons.


  30. CH₃CH₂COOH, CH₃COOH, HCOOH, CH₃OH
     Answer: CH₃OH
     Explanation: CH₃OH is alcohol; others are carboxylic acids.


  31. Propene, Propane, Butane, Butene
     Answer: Propane
     Explanation: Propane is alkane; others are unsaturated.


  32. Methanol, Ethanol, Propanol, Butene
     Answer: Butene
     Explanation: Butene is alkene; others are alcohols.


  33. CH₃CH₂OH, CH₃CH₂CH₂OH, C₃H₄, CH₃OH
     Answer: C₃H₄
     Explanation: C₃H₄ is alkyne; others are alcohols.


  34. Ethanol, Methane, Methanol, Propanol
     Answer: Methane
     Explanation: Methane is alkane; others are alcohols.


  35. C₂H₄, C₃H₆, C₄H₈, CH₄
     Answer: CH₄
     Explanation: CH₄ is alkane; others are alkenes.


  36. Methanol, Ethanol, Propanol, Butane
     Answer: Butane
     Explanation: Butane is alkane; others are alcohols.


  37. C₂H₂, C₃H₄, C₄H₆, C₅H₁₂
     Answer: C₅H₁₂
     Explanation: C₅H₁₂ is alkane; others are alkynes.


  38. CH₃CH₂OH, C₂H₄, CH₃OH, C₄H₁₀
     Answer: C₂H₄
     Explanation: C₂H₄ is alkene; others are alcohols or alkane.


  39. Ethanoic acid, Propanoic acid, Butanoic acid, Ethanol
     Answer: Ethanol
     Explanation: Ethanol is alcohol; others are carboxylic acids.


  40. Methane, Ethane, Propane, Butanol
     Answer: Butanol
     Explanation: Butanol is alcohol; others are alkanes.


  41. C₂H₄, C₃H₆, C₄H₈, C₄H₁₀
     Answer: C₄H₁₀
     Explanation: C₄H₁₀ is alkane; others are alkenes.


  42. Methanol, Ethanol, Propanol, Butyne
     Answer: Butyne
     Explanation: Butyne is alkyne; others are alcohols.


  43. CH₄, C₂H₆, C₂H₄, C₂H₂
     Answer: CH₄
     Explanation: CH₄ is alkane with one carbon; others have two carbons.


  44. Ethane, Ethene, Ethyne, Methanol
     Answer: Methanol
     Explanation: Methanol is alcohol; others are hydrocarbons.


  45. Propane, Propene, Propyne, Propanol
     Answer: Propanol
     Explanation: Propanol is alcohol; others are hydrocarbons.


  46. CH₃COOH, HCOOH, CH₃CH₂OH, C₂H₅COOH
     Answer: CH₃CH₂OH
     Explanation: Alcohol among acids.


  47. Ethene, Propene, Butene, Methane
     Answer: Methane
     Explanation: Methane is alkane; others are alkenes.


  48. CH₄, C₂H₆, C₃H₈, C₆H₆
     Answer: C₆H₆
     Explanation: C₆H₆ (benzene) is aromatic; others are alkanes.


  49. Methanol, Ethanol, Acetone, Butanol
     Answer: Acetone
     Explanation: Ketone among alcohols.


  50. CH₄, C₂H₄, C₃H₆, CH₃OH
     Answer: CH₃OH
     Explanation: Alcohol among hydrocarbons.

Match the Pair

Set 1

Match the following:

Column A

  1. Alkane with formula C₂H₆
  2. Functional group of alcohols
  3. General formula of alkenes
  4. Product of complete combustion of hydrocarbons
  5. Name of C₂H₂

Column B
 a) Ethyne
 b) CₙH₂ₙ
 c) Carbon dioxide and water
 d) Hydroxyl (-OH) group
 e) Ethane

 

Answers for Set 1:
 1 – e
 2 – d
 3 – b
 4 – c
 5 – a

Set 2

Match the following:

Column A

  1. Triple bond compound
  2. General formula of alkynes
  3. Alcohol that can be prepared by hydration of ethene
  4. Acidic organic compound
  5. Type of hydrocarbon with single bonds only

Column B
 a) Primary alcohol
 b) CₙH₂ₙ₋₂
 c) Carboxylic acid
 d) Alkane
 e) Alkyne

 

Answers for Set 2:
 1 – e
 2 – b
 3 – a
 4 – c
 5 – d

Set 3

Match the following:

Column A

  1. Functional group –COOH
  2. Alkene with formula C₃H₆
  3. Reaction turning bromine water colorless
  4. Ethanol reacts with sodium to produce
  5. Product of esterification reaction

Column B
 a) Water
 b) Propene
 c) Acid and alcohol
 d) Carboxylic acid
 e) Hydrogen gas

 

Answers for Set 3:
 1 – d
 2 – b
 3 – c
 4 – e
 5 – a

Set 4

Match the following:

Column A

  1. Smallest alkane
  2. Alkene general formula
  3. Compound with a triple bond
  4. Primary alcohol example
  5. Boiling point of alcohols compared to alkanes

Column B
 a) Methane
 b) Higher due to hydrogen bonding
 c) CₙH₂ₙ
 d) Ethanol
 e) Alkyne

 

Answers for Set 4:
 1 – a
 2 – c
 3 – e
 4 – d
 5 – b

Set 5

Match the following:

Column A

  1. Alkane undergoing substitution reaction
  2. Functional group in alcohol
  3. Acidity of carboxylic acids due to
  4. General formula of alkynes
  5. Ethyne’s common name

Column B
 a) Acidity of –COOH
 b) Methane
 c) Acetylene
 d) Hydroxyl (-OH) group
 e) CₙH₂ₙ₋₂

 

Answers for Set 5:
 1 – b
 2 – d
 3 – a
 4 – e
 5 – c

Set 6

Match the following:

Column A

  1. Reaction where alkene reacts with bromine
  2. Hydrocarbon with only single bonds
  3. Alcohol that is toxic
  4. Acid-base reaction produces
  5. Carbon-carbon bond in alkynes

Column B
 a) Salt and water
 b) Methanol
 c) Substitution
 d) Triple bond
 e) Alkane

 

Answers for Set 6:
 1 – c
 2 – e
 3 – b
 4 – a
 5 – d

Set 7

Match the following:

Column A

  1. Alkane with four carbon atoms
  2. Functional group in carboxylic acids
  3. Type of alcohol with hydroxyl group on a tertiary carbon
  4. Unsaturated hydrocarbon with double bond
  5. Product when ethanol burns

Column B
 a) Butane
 b) Carbon dioxide and water
 c) Tertiary alcohol
 d) –COOH group
 e) Alkene

 

Answers for Set 7:
 1 – a
 2 – d
 3 – c
 4 – e
 5 – b

Set 8

Match the following:

Column A

  1. Compound that decolorizes bromine water
  2. Alcohol with formula C₃H₈O
  3. Acid used in vinegar
  4. Type of bond in alkanes
  5. Alkene with formula C₂H₄

Column B
 a) Single bond
 b) Ethanoic acid
 c) Propanol
 d) Ethene
 e) Alkene

 

Answers for Set 8:
 1 – e
 2 – c
 3 – b
 4 – a
 5 – d

Set 9

Match the following:

Column A

  1. Compound with formula C₄H₈
  2. Alcohol reaction with sodium metal produces
  3. Functional group that determines acidity in carboxylic acids
  4. Formula representing alkanes
  5. Example of an alkene

Column B
 a) Hydrogen gas
 b) CₙH₂ₙ₊₂
 c) Butene
 d) –COOH
 e) Alkene

 

Answers for Set 9:
 1 – c
 2 – a
 3 – d
 4 – b
 5 – e

Set 10

Match the following:

Column A

  1. Alkyne with two carbon atoms
  2. Alcohol that can be dehydrated to form alkene
  3. Acid that reacts with alcohol to form ester
  4. Type of reaction where alkane reacts with halogen
  5. Compound with formula C₃H₆

Column B
 a) Propene
 b) Ethyne
 c) Substitution reaction
 d) Carboxylic acid
 e) Ethanol

 

Answers for Set 10:
 1 – b
 2 – e
 3 – d
 4 – c
 5 – a

Short Answer Questions  

  1. What is the general formula of alkanes?
     CₙH₂ₙ₊₂


  2. Name the simplest alkane.
     Methane (CH₄)


  3. What type of bond is present between carbon atoms in alkanes?
     Single covalent bond


  4. Write the molecular formula of ethene.
     C₂H₄


  5. What is the functional group of alkenes?
     Carbon-carbon double bond (C=C)


  6. Give the general formula of alkynes.
     CₙH₂ₙ₋₂


  7. What is the common name of ethyne?
     Acetylene


  8. Write the molecular formula of ethanol.
     C₂H₅OH


  9. What functional group is present in alcohols?
     Hydroxyl group (–OH)


  10. What is the IUPAC name of CH₃COOH?
     Ethanoic acid


  11. Write the general formula of alcohols.
     CₙH₂ₙ₊₁OH


  12. Name the process by which ethene reacts with hydrogen to form ethane.
     Hydrogenation


  13. What is the product when an alcohol reacts with sodium metal?
     Sodium alkoxide and hydrogen gas


  14. Which gas is released when alcohol reacts with sodium?
     Hydrogen (H₂)


  15. Write the molecular formula of propene.
     C₃H₆


  16. Name the type of reaction in which bromine water decolorizes in presence of alkenes.
     Addition reaction


  17. What is esterification?
     Reaction between an alcohol and a carboxylic acid forming an ester and water


  18. Write the structural formula of methane.
     CH₄


  19. Give an example of a tertiary alcohol.
     2-methyl-2-propanol


  20. What is the common name of methanol?
     Wood alcohol


  21. Name the reaction when an alkane reacts with chlorine under UV light.
     Substitution reaction


  22. Which functional group imparts acidic properties to carboxylic acids?
     Carboxyl group (–COOH)


  23. Write the balanced chemical equation for the complete combustion of methane.
     CH₄ + 2O₂ → CO₂ + 2H₂O


  24. What type of isomerism is shown by butane and methylpropane?
     Structural isomerism


  25. What is the IUPAC name of CH₃CH₂CH₂OH?
     Propan-1-ol


  26. Give the product formed when ethanol is dehydrated.
     Ethene and water


  27. What type of bond is present in the triple bond of alkynes?
     One sigma and two pi bonds


  28. What is the molecular formula of butyne?
     C₄H₆


  29. Write the name of an alkyne with three carbon atoms.
     Propyne


  30. What is the use of bromine water test in organic chemistry?
     To identify unsaturation (presence of double or triple bonds)


  31. Name the homologous series to which methane belongs.
     Alkane series


  32. What is the IUPAC name of the compound CH₃CH=CH₂?
     Propene


  33. What is the effect of hydrogen bonding on the boiling points of alcohols?
     It raises boiling points compared to alkanes of similar molecular weight


  34. Write the molecular formula of ethanoic acid.
     CH₃COOH


  35. Name the reaction when alkenes react with halogens.
     Addition reaction


  36. What is the IUPAC name of CH₃CH₂COOH?
     Propanoic acid


  37. Give an example of a primary alcohol.
     Ethanol


  38. What product is formed by the complete combustion of ethanol?
     Carbon dioxide and water


  39. What is the common name of ethanoic acid?
     Acetic acid


  40. Write the molecular formula of cyclohexane.
     C₆H₁₂


  41. What type of hydrocarbons are alkanes?
     Saturated hydrocarbons


  42. Write the general formula of cycloalkanes.
     CₙH₂ₙ


  43. Name the process by which alcohols are converted to alkenes.
     Dehydration


  44. What is the IUPAC name of CH₃CH₂OH?
     Ethanol


  45. Write the molecular formula of propane.
     C₃H₈


  46. Which compound has the formula C₂H₂?
     Ethyne


  47. Name the compound CH₃CH₂CH₂CH₃.
     Butane


  48. What is the product when alkenes undergo hydrogenation?
     Alkanes


  49. Write the molecular formula of phenol.
     C₆H₅OH


  50. What is the general formula of alkenes showing one double bond?
     CₙH₂ₙ

Puzzles


  1. Puzzle: Identify the alkane with the molecular formula C₄H₁₀ that has two isomers.
    Answer: Butane and Isobutane (Methylpropane).

  2. Puzzle: Name the alkene with the formula C₃H₆ that decolorizes bromine water.
    Answer: Propene.

  3. Puzzle: Which compound is a primary alcohol with the formula C₂H₅OH?
    Answer: Ethanol.

  4. Puzzle: Which hydrocarbon contains a triple bond and has the formula C₂H₂?
    Answer: Ethyne (Acetylene).

  5. Puzzle: Name the compound with formula C₂H₄ that undergoes addition reactions.
    Answer: Ethene.

  6. Puzzle: Identify the carboxylic acid with the formula CH₃COOH.
    Answer: Ethanoic acid (Acetic acid).

  7. Puzzle: Find the odd one out: Methane, Ethane, Ethene, Propane.
    Answer: Ethene (because it contains a double bond; others are alkanes).

  8. Puzzle: Which alkane is commonly used as LPG fuel?
    Answer: Propane.

  9. Puzzle: Name the isomer of C₅H₁₂ with a branched chain.
    Answer: 2-Methylbutane or 2,2-Dimethylpropane.

  10. Puzzle: Which alcohol is used in antiseptics and has the formula C₃H₇OH?
    Answer: Isopropanol (Isopropyl alcohol).

  11. Puzzle: Identify the functional group responsible for the acidic nature of carboxylic acids.
    Answer: –COOH (Carboxyl group).

  12. Puzzle: Which alkene can be formed by the dehydration of ethanol?
    Answer: Ethene.

  13. Puzzle: Name the simplest alkyne.
    Answer: Ethyne.

  14. Puzzle: Which compound is a tertiary alcohol: 2-propanol or 2-methyl-2-propanol?
    Answer: 2-Methyl-2-propanol.

  15. Puzzle: Identify the alkane which is a major component of natural gas.
    Answer: Methane.

  16. Puzzle: Which alkene is used to manufacture polyethylene?
    Answer: Ethene.

  17. Puzzle: Which alkyne is used as a fuel in oxyacetylene welding?
    Answer: Ethyne.

  18. Puzzle: Name the compound CH₃CH₂OH.
    Answer: Ethanol.

  19. Puzzle: Which carboxylic acid is commonly found in vinegar?
    Answer: Ethanoic acid.

  20. Puzzle: Find the odd one out: Propene, Butyne, Butane, Ethyne.
    Answer: Butane (alkane; others unsaturated hydrocarbons).

  21. Puzzle: Which functional group is present in all alcohols?
    Answer: Hydroxyl group (–OH).

  22. Puzzle: What is the general formula for alkanes?
    Answer: CₙH₂ₙ₊₂.

  23. Puzzle: Which alkene has a double bond between the first and second carbon atoms?
    Answer: 1-Butene.

  24. Puzzle: Name the compound CH₃CH=CH₂.
    Answer: Propene.

  25. Puzzle: Which compound with formula C₄H₆ is an alkyne?
    Answer: Butyne.

  26. Puzzle: Identify the simplest carboxylic acid.
    Answer: Methanoic acid (Formic acid).

  27. Puzzle: Which alcohol is commonly used as a solvent and has the formula CH₃CH₂OH?
    Answer: Ethanol.

  28. Puzzle: Which hydrocarbon family contains only single bonds?
    Answer: Alkanes.

  29. Puzzle: What is the general formula for alkenes?
    Answer: CₙH₂ₙ.

  30. Puzzle: Which reaction converts an alkene to an alkane by adding hydrogen?
    Answer: Hydrogenation.

  31. Puzzle: Name the compound with formula C₃H₄, an alkyne.
    Answer: Propyne.

  32. Puzzle: Which alkane has the formula C₃H₈?
    Answer: Propane.

  33. Puzzle: Find the odd one out: Ethanol, Methanol, Ethene, Propanol.
    Answer: Ethene (not an alcohol).

  34. Puzzle: Which alkyne has a triple bond between the first and second carbon?
    Answer: 1-Butyne.

  35. Puzzle: Which is the only alkyne with no isomers?
    Answer: Ethyne.

  36. Puzzle: Name the alkane with six carbon atoms.
    Answer: Hexane.

  37. Puzzle: Which compound is an unsaturated hydrocarbon with formula C₅H₁₀?
    Answer: Pentene.

  38. Puzzle: Which alcohol is used as fuel and disinfectant and has formula CH₃OH?
    Answer: Methanol.

  39. Puzzle: Which carboxylic acid has a pungent smell and is used in food preservation?
    Answer: Ethanoic acid.

  40. Puzzle: Find the odd one out: Ethyne, Ethene, Ethane, Methanol.
    Answer: Methanol (an alcohol, others hydrocarbons).

  41. Puzzle: Name the product when ethene reacts with bromine water.
    Answer: 1,2-Dibromoethane.

  42. Puzzle: Which alkane is a major component of gasoline?
    Answer: Octane.

  43. Puzzle: What is the molecular formula of propane?
    Answer: C₃H₈.

  44. Puzzle: Which alcohol is formed by the hydration of ethene?
    Answer: Ethanol.

  45. Puzzle: Name the acid with formula HCOOH.
    Answer: Methanoic acid.

  46. Puzzle: Which compound can be formed by oxidation of ethanol?
    Answer: Ethanal (acetaldehyde).

  47. Puzzle: Which alkene has the formula C₂H₄?
    Answer: Ethene.

  48. Puzzle: What is the common name of CH₃COOH?
    Answer: Acetic acid.

  49. Puzzle: Which alkane is a gas at room temperature and used for heating?
    Answer: Methane.

  50. Puzzle: Which is the product when ethyne undergoes addition of hydrogen in the presence of a catalyst?
    Answer: Ethene, and further hydrogenation forms ethane.

Difference Between:

  1. Difference between Alkanes and Alkenes
    Alkanes: Saturated hydrocarbons containing only single bonds between carbon atoms (e.g., C₂H₆).
    Alkenes: Unsaturated hydrocarbons containing at least one double bond between carbon atoms (e.g., C₂H₄).

 

  1. Difference between Alkenes and Alkynes
    Alkenes: Contain one or more double bonds (C=C).
    Alkynes: Contain one or more triple bonds (C≡C).

 

  1. Difference between Saturated and Unsaturated Hydrocarbons
    Saturated Hydrocarbons: Contain only single covalent bonds (e.g., CH₄).
    Unsaturated Hydrocarbons: Contain double or triple bonds (e.g., C₂H₄, C₂H₂).

 

  1. Difference between Ethane and Ethene
    Ethane (C₂H₆): An alkane with only single bonds.
    Ethene (C₂H₄): An alkene with one double bond between carbon atoms.

 

  1. Difference between Ethene and Ethyne
    Ethene (C₂H₄): Contains a double bond.
    Ethyne (C₂H₂): Contains a triple bond.

 

  1. Difference between Alkanes and Alkynes
    Alkanes: General formula CₙH₂ₙ₊₂; single bonds only.
    Alkynes: General formula CₙH₂ₙ₋₂; triple bonds present.

 

  1. Difference between Alcohol and Carboxylic Acid
    Alcohol: Contains –OH functional group (e.g., C₂H₅OH).
    Carboxylic Acid: Contains –COOH functional group (e.g., CH₃COOH).

 

  1. Difference between Ethanol and Acetic Acid
    Ethanol (C₂H₅OH): A neutral compound with alcoholic properties.
    Acetic Acid (CH₃COOH): An acidic compound with sour taste and pH < 7.

 

  1. Difference between Addition and Substitution Reactions
    Addition Reaction: Characteristic of alkenes and alkynes; new atoms are added to the molecule.
    Substitution Reaction: Characteristic of alkanes; one atom is replaced by another.

 

  1. Difference between Primary and Secondary Alcohols
    Primary Alcohol: –OH group attached to a carbon with one alkyl group (e.g., CH₃CH₂OH).
    Secondary Alcohol: –OH group attached to a carbon with two alkyl groups (e.g., CH₃CHOHCH₃).

 

  1. Difference between Combustion and Oxidation of Hydrocarbons
    Combustion: Complete burning in oxygen to give CO₂ and H₂O.
    Oxidation: Controlled process converting alcohol to acid or alkene to diol.

 

  1. Difference between Functional Group and Homologous Series
    Functional Group: Specific atom/group responsible for characteristic reactions (e.g., –OH).
    Homologous Series: Series of compounds with same functional group and similar properties.

 

  1. Difference between Ethanol and Methanol
    Ethanol (C₂H₅OH): Common alcohol used in beverages and antiseptics.
    Methanol (CH₃OH): Highly toxic alcohol used as industrial solvent and fuel.

 

  1. Difference between Ethanoic Acid and Formic Acid
    Ethanoic Acid (CH₃COOH): Has a methyl group attached to –COOH.
    Formic Acid (HCOOH): Simplest carboxylic acid with no alkyl group.

 

  1. Difference between Monohydric and Polyhydric Alcohols
    Monohydric Alcohol: Contains one –OH group (e.g., CH₃CH₂OH).
    Polyhydric Alcohol: Contains more than one –OH group (e.g., CH₂OH–CHOH–CH₂OH).

 

  1. Difference between Ethanol and Ethanoic Acid in Litmus Test
    Ethanol: Neutral; does not change litmus.
    Ethanoic Acid: Acidic; turns blue litmus red.

 

  1. Difference between Substitution and Addition in Hydrocarbon Reactions
    Substitution: Involves replacement of atoms (typical of alkanes).
    Addition: Involves breaking of π bonds and adding new atoms (typical of alkenes/alkynes).

 

  1. Difference between Decolorization of Bromine Water by Alkene and Alkane
    Alkene: Decolorizes bromine water via addition.
    Alkane: Does not decolorize bromine water unless exposed to UV light (substitution).

 

  1. Difference between Acidic and Neutral Organic Compounds
    Acidic Compounds: Contain –COOH group (e.g., CH₃COOH); pH < 7.
    Neutral Compounds: Contain –OH group (e.g., CH₃CH₂OH); pH ≈ 7.

 

  1. Difference between Organic and Inorganic Compounds
    Organic Compounds: Contain carbon-hydrogen bonds (e.g., hydrocarbons, alcohols).
    Inorganic Compounds: Do not contain C–H bonds; derived from non-living matter.

Assertion and Reason

Assertion (A) and Reason (R)

  1.  

Assertion (A): Alkanes are saturated hydrocarbons.
 Reason (R): Alkanes contain only single bonds between carbon atoms.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethene is an unsaturated hydrocarbon.
 R: Ethene contains a carbon-carbon double bond.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkyne hydrocarbons have a triple bond.
 R: A triple bond consists of one sigma and two pi bonds.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alcohols contain a hydroxyl group (-OH).
 R: The hydroxyl group makes alcohols polar compounds.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids have the functional group –COOH.
 R: The –COOH group contains both a carbonyl and a hydroxyl group.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethanol reacts with sodium metal to release hydrogen gas.
 R: Sodium displaces hydrogen from alcohols due to its reactivity.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Bromine water turns colorless in presence of alkenes.
 R: Alkenes undergo addition reaction with bromine, removing its color.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Methane has the formula CH₄.
 R: Methane is the simplest alkane.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Propene is an alkene.
 R: Propene contains one double bond between carbon atoms.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Complete combustion of hydrocarbons produces carbon dioxide and water.
 R: Hydrocarbons contain carbon and hydrogen which oxidize completely during combustion.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethyne is more reactive than ethane.
 R: Ethyne has a triple bond which is more reactive than single bonds in ethane.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethanol can be prepared by hydration of ethene.
 R: Hydration adds water across the double bond of ethene to form ethanol.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids are acidic in nature.
 R: The –COOH group releases H⁺ ions in aqueous solution.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: The general formula of alkenes is CₙH₂ₙ.
 R: Alkenes have one carbon-carbon double bond reducing the hydrogen count by two.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkynes have the general formula CₙH₂ₙ₋₂.
 R: Alkynes have one triple bond which reduces hydrogen atoms by four compared to alkanes.
 Answer: Both A and R are true, but R is not the correct explanation of A.

  1.  

A: Alcohols are classified into primary, secondary, and tertiary.
 R: Classification depends on the number of alkyl groups attached to the carbon bearing –OH group.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids react with metals to produce hydrogen gas.
 R: Metals displace hydrogen from acids due to acid’s ability to ionize.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethene undergoes addition reactions.
 R: The presence of a double bond makes ethene unsaturated and reactive.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkanes do not undergo addition reactions.
 R: Alkanes have only single bonds, making them saturated and less reactive towards addition.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids have higher boiling points than alcohols.
 R: Carboxylic acids form dimers through hydrogen bonding, increasing boiling point.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Methane does not react with bromine in absence of light.
 R: Bromination of methane requires ultraviolet light for initiation.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkynes are more reactive than alkenes.
 R: Triple bonds contain more pi bonds, which are reactive.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alcohols burn with a blue flame.
 R: Alcohol combustion is complete and produces blue flame.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkanes undergo substitution reactions.
 R: Alkanes lack double or triple bonds so substitution is the typical reaction.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethyne is used in welding torches.
 R: Ethyne burns with a very hot flame due to high heat of combustion.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Propanol has the molecular formula C₃H₈O.
 R: Propanol is an alcohol with three carbon atoms and one hydroxyl group.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Butane has the formula C₄H₁₀.
 R: Butane is an alkane with four carbon atoms and single bonds only.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids have pungent odors.
 R: The –COOH group causes the characteristic smell.
 Answer: Both A and R are true, but R is not the correct explanation of A.

  1.  

A: Ethanol is miscible with water.
 R: The polar –OH group in ethanol forms hydrogen bonds with water.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: The combustion of alkanes produces soot.
 R: Incomplete combustion leads to carbon (soot) formation.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkynes undergo addition reactions.
 R: Triple bonds in alkynes can open to add atoms.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Methanoic acid is also called formic acid.
 R: Methanoic acid is found in ant venom.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alcohols are soluble in water.
 R: Hydrogen bonding between –OH group and water makes alcohols soluble.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkenes are named with the suffix –ene.
 R: The suffix –ene denotes the presence of a double bond.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkanes are less reactive than alkenes.
 R: Saturated bonds in alkanes make them less reactive.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Butyne has four carbon atoms.
 R: Butyne contains a triple bond and four carbons.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids react with alcohols to form esters.
 R: Esterification is a reaction between acid and alcohol.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethene is used to ripen fruits.
 R: Ethene acts as a plant hormone stimulating ripening.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Propane is a saturated hydrocarbon.
 R: Propane contains only single bonds between carbon atoms.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkenes react with hydrogen halides.
 R: The double bond in alkenes breaks to add the halide.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alcohols undergo dehydration reactions.
 R: Dehydration removes water to form alkenes.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethyne is also called acetylene.
 R: Acetylene is the common name of ethyne.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: The boiling point of alcohols is higher than that of alkanes.
 R: Alcohols have hydrogen bonding while alkanes do not.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Propanoic acid contains three carbon atoms.
 R: Propanoic acid is a carboxylic acid with a three-carbon chain.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkanes undergo combustion reactions.
 R: Combustion involves reacting with oxygen to form CO₂ and H₂O.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Alkynes have higher acidity than alkanes.
 R: The hydrogen attached to the sp carbon in alkynes is more acidic.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Ethene decolorizes bromine water.
 R: Bromine adds across the double bond in ethene.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Methanol is toxic to humans.
 R: Methanol metabolizes to formaldehyde, which is poisonous.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: The triple bond in alkynes is linear.
 R: The sp hybridization in alkynes causes linear geometry.
 Answer: Both A and R are true, and R is the correct explanation of A.

  1.  

A: Carboxylic acids react with bases to form salts.
 R: Acid-base reaction produces salt and water.
 Answer: Both A and R are true, and R is the correct explanation of A.

True or False

  1. Alkynes contain at least one double bond between carbon atoms. — False
  2. Ethanol has the molecular formula C₂H₅OH. — True
  3. Carboxylic acids contain the functional group –OH. — False
  4. Methane (CH₄) is the simplest alkane. — True
  5. Alkenes are more reactive than alkanes due to the presence of a double bond. — True
  6. Propene is an example of an alkyne. — False
  7. Alcohols can be classified as primary, secondary, or tertiary based on the carbon to which –OH is attached. — True
  8. Ethyne is also called acetylene. — True
  9. The functional group of carboxylic acids is –COOH. — True
  10. Alkanes undergo substitution reactions under UV light. — True
  11. Alkenes undergo addition reactions with bromine water, turning it colorless. — True
  12. Alkynes have the general formula CₙH₂ₙ. — False
  13. Alcohols have higher boiling points than alkanes of similar molecular weight due to hydrogen bonding. — True
  14. Ethanoic acid is commonly known as vinegar. — True
  15. Complete combustion of hydrocarbons produces carbon monoxide and water. — False
  16. The bond between carbon atoms in alkanes is a single covalent bond. — True
  17. Butane is an alkene with four carbon atoms. — False
  18. Propanol is an example of a primary alcohol. — True
  19. Alkenes contain a triple bond between carbon atoms. — False
  20. The addition of hydrogen to alkenes is called hydrogenation. — True
  21. Alkynes react with bromine water to form a colorless solution. — True
  22. Ethanol reacts with sodium metal to produce sodium ethoxide and hydrogen gas. — True
  23. The molecular formula C₃H₆ corresponds to an alkene. — True
  24. Carboxylic acids are acidic because of the presence of the hydroxyl group. — False
  25. Alkanes are insoluble in water but soluble in organic solvents. — True
  26. Ethene and ethyne have the same molecular formula. — False
  27. Tertiary alcohols have the –OH group attached to a carbon atom bonded to three other carbon atoms. — True
  28. The boiling point of methane is higher than that of ethanol. — False
  29. Alkynes have a carbon-carbon triple bond. — True
  30. Decane is an alkane with 12 carbon atoms. — False
  31. Bromine water remains orange when added to an alkane. — True
  32. Esterification is a reaction between an alcohol and a carboxylic acid. — True
  33. The name “ethane” refers to an alkene. — False
  34. The functional group in alcohols is –OH. — True
  35. Complete combustion of alkanes produces carbon dioxide and water. — True
  36. Alkenes do not exhibit isomerism. — False
  37. Methanol is toxic and not suitable for drinking. — True
  38. Ethyne is a saturated hydrocarbon. — False
  39. The general formula for alcohols is CₙH₂ₙ₊₁OH. — True
  40. Alkanes are generally more reactive than alkenes. — False
  41. Propane undergoes substitution reactions in the presence of UV light. — True
  42. Ethanoic acid is a weak acid. — True
  43. Alkenes can be converted to alkanes by addition of hydrogen. — True
  44. Alkynes cannot undergo addition reactions. — False
  45. The carbon-carbon bond length in alkanes is longer than in alkenes. — True
  46. Alcohols can be dehydrated to form alkenes. — True
  47. The triple bond in alkynes consists of one sigma and two pi bonds. — True
  48. The IUPAC name for CH₃CH₂OH is methanol. — False
  49. Alkanes are saturated hydrocarbons containing only single bonds. — True
  50. The general formula for alkenes is CₙH₂ₙ. — True

Long Answer Questions

  1. Explain the general characteristics and uses of alkanes.
     Alkanes are saturated hydrocarbons with the general formula CₙH₂ₙ₊₂. They contain only single covalent bonds between carbon atoms, making them relatively less reactive. Alkanes are generally colorless, odorless gases or liquids. They are found in natural gas and petroleum and are widely used as fuels (e.g., methane, propane) and as starting materials for the manufacture of various chemicals.


  2. Describe the structure and bonding in alkenes.
     Alkenes are unsaturated hydrocarbons containing at least one carbon-carbon double bond (C=C). The general formula is CₙH₂ₙ. Each carbon in the double bond forms three sigma bonds using sp² hybrid orbitals, and the remaining p orbitals overlap sideways to form a pi bond. This double bond restricts rotation, leading to cis-trans isomerism.


  3. Write the IUPAC naming rules for alkanes with an example.
     The IUPAC naming of alkanes involves identifying the longest carbon chain, numbering it from the end nearest to a substituent, and naming substituents alphabetically with their position numbers. For example, CH₃–CH(CH₃)–CH₃ is named 2-methylpropane because the longest chain is propane and the methyl group is on carbon 2.


  4. Explain addition reactions of alkenes with suitable examples.
     Alkenes undergo addition reactions where the double bond breaks and atoms add to the carbons. For example, ethene reacts with bromine (Br₂) in an addition reaction to form 1,2-dibromoethane:
     C₂H₄ + Br₂ → C₂H₄Br₂
     This reaction is used as a test for unsaturation.


  5. What are isomers? Explain structural isomerism with examples from alkanes.
     Isomers are compounds with the same molecular formula but different structural formulas. Structural isomerism occurs when atoms are connected differently. For example, C₄H₁₀ has two isomers: butane (a straight chain) and methylpropane (a branched chain).


  6. Describe the preparation and properties of ethanol.
     Ethanol (C₂H₅OH) can be prepared by fermentation of sugars or by hydration of ethene. It is a colorless, volatile liquid miscible with water. Ethanol burns with a clean flame and reacts with sodium metal to release hydrogen gas, showing its acidic hydrogen in the –OH group.


  7. Write the chemical equation and explain the reaction of ethanol with sodium metal.
     C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑
     Ethanol reacts with sodium metal to form sodium ethoxide and hydrogen gas. The hydrogen gas released can be observed as bubbles, indicating the presence of acidic hydrogen in alcohols.


  8. Explain the acidity of carboxylic acids.
     Carboxylic acids contain the –COOH group, which can donate a proton (H⁺) making them acidic. The resonance stabilization of the carboxylate ion (R–COO⁻) formed after loss of H⁺ enhances acidity. For example, ethanoic acid partially dissociates in water releasing H⁺ ions.


  9. Describe the esterification reaction and give an example.
     Esterification is a reaction between a carboxylic acid and an alcohol in the presence of an acid catalyst, forming an ester and water.
     Example: Ethanoic acid reacts with ethanol to form ethyl ethanoate:
     CH₃COOH + C₂H₅OH ⇌ CH₃COOC₂H₅ + H₂O


  10. Compare the physical properties of alkanes and alcohols.
     Alkanes are non-polar, insoluble in water, and have low boiling points. Alcohols contain the polar hydroxyl group (–OH) which forms hydrogen bonds, leading to higher boiling points and solubility in water compared to alkanes of similar molecular weight.


  11. Explain the mechanism of bromine water test for unsaturation.
     Bromine water is orange-brown and reacts with alkenes or alkynes, adding across the multiple bonds and decolorizing the solution. For example, ethene reacts with bromine water, turning it colorless due to the addition reaction.


  12. Write the complete combustion reaction of propane.
     C₃H₈ + 5O₂ → 3CO₂ + 4H₂O
     Propane burns in excess oxygen to produce carbon dioxide and water, releasing energy.


  13. Explain the difference between primary, secondary, and tertiary alcohols with examples.
     Primary alcohols have the –OH group attached to a carbon bonded to only one other carbon (e.g., ethanol). Secondary alcohols have –OH attached to a carbon bonded to two carbons (e.g., isopropanol). Tertiary alcohols have –OH on a carbon bonded to three carbons (e.g., 2-methyl-2-propanol).


  14. Describe the process of fractional distillation of crude oil.
     Crude oil is heated, and its components are separated by boiling points in a fractionating column. Light fractions like gases and petrol vaporize at lower temperatures and rise higher, while heavier fractions like lubricating oil remain lower.


  15. Write the chemical formula and structure of acetylene.
     C₂H₂, with a triple bond between two carbon atoms: H–C≡C–H.


  16. Explain substitution reaction in alkanes with an example.
     Alkanes react with halogens in the presence of UV light where a hydrogen atom is replaced by a halogen atom. For example, methane reacts with chlorine to form chloromethane and HCl:
     CH₄ + Cl₂ → CH₃Cl + HCl


  17. What is the role of a catalyst in the hydration of ethene?
     An acid catalyst like sulfuric acid (H₂SO₄) is required to add water (H₂O) across the double bond of ethene to form ethanol.


  18. Explain the molecular structure and hybridization of ethene.
     In ethene (C₂H₄), each carbon is sp² hybridized, forming three sigma bonds and one pi bond. The molecule is planar with a bond angle of about 120°.


  19. Write a balanced chemical equation for the dehydration of ethanol.
     C₂H₅OH → C₂H₄ + H₂O (in presence of concentrated H₂SO₄ and heat)


  20. Describe the physical state and solubility of carboxylic acids.
     Lower carboxylic acids are colorless liquids with strong, pungent smell and are soluble in water due to hydrogen bonding. Solubility decreases with increasing chain length.


  21. Explain the term ‘unsaturated hydrocarbon’.
     Hydrocarbons that contain one or more carbon-carbon double or triple bonds and can undergo addition reactions are called unsaturated hydrocarbons (alkenes and alkynes).


  22. Write the IUPAC name of CH₃–CH₂–CH₂–OH and mention its classification.
     Propan-1-ol; primary alcohol


  23. Describe the test for distinguishing between an alkane and an alkene.
     Add bromine water to both samples. Alkene decolorizes bromine water due to addition reaction; alkane does not react and bromine water remains colored.


  24. Explain why alkanes are less reactive compared to alkenes.
     Alkanes have only single bonds which are strong and non-polar, making them chemically inert under normal conditions. Alkenes have reactive double bonds that readily undergo addition reactions.


  25. Give an example and write the formula of a branched-chain alkane.
     2-methylpropane (isobutane); C₄H₁₀


  26. Describe the physical properties of alcohols that distinguish them from hydrocarbons.
     Alcohols have higher boiling points due to hydrogen bonding, are polar and soluble in water, unlike hydrocarbons which are non-polar and insoluble.


  27. Explain why ethanol is miscible with water.
     Ethanol forms hydrogen bonds with water molecules because of its –OH group, allowing it to mix in all proportions.


  28. Write the chemical equation for the reaction of ethene with hydrogen bromide.
     C₂H₄ + HBr → C₂H₅Br


  29. Describe the industrial preparation of ethyne.
     Ethyn e is prepared by the reaction of calcium carbide (CaC₂) with water:
     CaC₂ + 2H₂O → C₂H₂ + Ca(OH)₂


  30. Explain the difference between saturated and unsaturated hydrocarbons.
     Saturated hydrocarbons have single bonds only (alkanes), while unsaturated have one or more double/triple bonds (alkenes, alkynes).


  31. Describe the test to identify the presence of a carboxyl group.
     Carboxylic acids react with sodium carbonate to produce carbon dioxide gas, observed as effervescence:
     2RCOOH + Na₂CO₃ → 2RCOONa + CO₂ + H₂O


  32. Write the chemical equation for the esterification of ethanoic acid and methanol.
     CH₃COOH + CH₃OH ⇌ CH₃COOCH₃ + H₂O


  33. Explain why alkenes show cis-trans isomerism.
     Due to the restricted rotation around the C=C double bond, substituents can be arranged differently in space, leading to cis (same side) and trans (opposite side) isomers.


  34. Write the molecular formula of 1-butyne and draw its structure.
     C₄H₆; CH≡C–CH₂–CH₃


  35. Explain the term ‘hydrocarbon’. Give examples.
     Hydrocarbons are organic compounds composed solely of carbon and hydrogen atoms. Examples include methane (CH₄), ethene (C₂H₄), and ethyne (C₂H₂).


  36. Describe the process of fermentation for ethanol production.
     Sugars such as glucose undergo anaerobic fermentation by yeast enzymes producing ethanol and carbon dioxide:
     C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂


  37. Write the equation for the reaction of methane with chlorine under UV light.
     CH₄ + Cl₂ → CH₃Cl + HCl


  38. Describe how boiling points change with increasing carbon chain length in alkanes.
     Boiling points increase with chain length due to greater van der Waals forces between molecules.


  39. Write the name and formula of the alkane with 5 carbon atoms.
     Pentane, C₅H₁₂


  40. Explain the role of hydrogen bonding in the properties of alcohols.
     Hydrogen bonding between –OH groups raises boiling points and increases solubility in water.


  41. Describe the difference between complete and incomplete combustion of hydrocarbons.
     Complete combustion produces CO₂ and H₂O; incomplete combustion produces CO, C (soot), and H₂O.


  42. Write the chemical equation for the addition of chlorine to ethene.
     C₂H₄ + Cl₂ → C₂H₄Cl₂


  43. Explain the term ‘functional group’ with examples from organic chemistry.
     A functional group is a specific group of atoms responsible for characteristic reactions of a compound, e.g., –OH in alcohols, –COOH in carboxylic acids.


  44. Describe the use of carboxylic acids in daily life.
     Carboxylic acids like ethanoic acid are used in vinegar, food preservation, and manufacturing of pharmaceuticals and plastics.


  45. Write the molecular formula of 2-propanol and classify it.
     C₃H₈O; secondary alcohol


  46. Explain the concept of resonance in carboxylate ions.
     The negative charge on the carboxylate ion (R–COO⁻) is delocalized between the two oxygen atoms, stabilizing the ion.


  47. Describe the preparation of ethane by hydrogenation of ethene.
     Ethene reacts with hydrogen in presence of a nickel catalyst to form ethane:
     C₂H₄ + H₂ → C₂H₆


  48. Explain the role of catalysts in organic reactions with an example.
     Catalysts speed up reactions without being consumed. For example, sulfuric acid catalyzes the hydration of ethene to ethanol.


  49. Write the equation for the reaction of propanol with sodium metal.
     C₃H₇OH + 2Na → 2C₃H₇ONa + H₂↑


  50. Explain how the structure of alkanes affects their physical properties.
     Straight-chain alkanes have higher boiling points than branched isomers due to stronger van der Waals forces and better molecular packing.

Give Reasons

  1. Give reason why alkanes are called saturated hydrocarbons.
     Alkanes contain only single bonds between carbon atoms, and each carbon is saturated with the maximum number of hydrogen atoms possible, making them saturated hydrocarbons.


  2. Give reason why alkenes are more reactive than alkanes.
     Alkenes contain a carbon-carbon double bond (C=C) which has a pi bond that is less stable and more reactive than the single bonds in alkanes, making alkenes more reactive.


  3. Give reason why alkanes undergo substitution reactions and not addition reactions.
     Alkanes have only single bonds, so they are saturated and cannot add atoms; instead, they undergo substitution where one atom replaces another.


  4. Give reason why alkenes undergo addition reactions.
     The double bond in alkenes can break to allow atoms to add across it, thus undergoing addition reactions.


  5. Give reason why ethanol is miscible with water.
     Ethanol has a polar –OH group capable of hydrogen bonding with water molecules, making it completely miscible with water.


  6. Give reason why carboxylic acids are acidic.
     The –COOH group can donate a proton (H⁺) because the negative charge formed after donation is stabilized by resonance, making carboxylic acids acidic.


  7. Give reason why methane does not react easily with bromine in the dark.
     Methane requires UV light to initiate the substitution reaction with bromine because UV light provides the energy needed to break the Br–Br bond.


  8. Give reason why alkenes show cis-trans isomerism but alkanes do not.
     Alkenes have restricted rotation around the double bond, allowing different spatial arrangements (cis and trans), whereas alkanes have free rotation about single bonds.


  9. Give reason why boiling points of alcohols are higher than those of alkanes of similar molecular mass.
     Alcohols form hydrogen bonds between molecules due to –OH groups, requiring more energy to break intermolecular forces, leading to higher boiling points.


  10. Give reason why ethene is planar in structure.
     In ethene, the carbons are sp² hybridized, forming a trigonal planar shape around each carbon with bond angles of approximately 120°.


  11. Give reason why alkanes are insoluble in water.
     Alkanes are non-polar molecules and cannot form hydrogen bonds with water, which is polar, resulting in their insolubility.


  12. Give reason why addition of bromine water to alkenes decolorizes the bromine solution.
     The bromine adds across the double bond in alkenes, removing the colored bromine from solution and decolorizing it.


  13. Give reason why tertiary alcohols do not oxidize easily.
     Tertiary alcohols lack a hydrogen atom on the carbon bearing the –OH group, which is necessary for oxidation, so they resist oxidation.


  14. Give reason why alkenes have the general formula CₙH₂ₙ.
     Alkenes contain one double bond and are unsaturated, so they have two fewer hydrogen atoms than the corresponding alkane (CₙH₂ₙ₊₂), resulting in CₙH₂ₙ.


  15. Give reason why alkanes have low reactivity.
     Alkanes have strong C–C and C–H single bonds and are non-polar, making them chemically inert under normal conditions.


  16. Give reason why carboxylic acids have higher boiling points than alcohols.
     Carboxylic acids can form dimers via two hydrogen bonds, doubling intermolecular forces, thus requiring more energy to boil.


  17. Give reason why ethanol burns with a clean flame.
     Ethanol undergoes complete combustion producing only CO₂ and H₂O, which do not produce soot, so the flame is clean.


  18. Give reason why ethyne has a linear structure.
     The carbon atoms in ethyne are sp hybridized, resulting in a linear molecule with a bond angle of 180°.


  19. Give reason why alkanes can be used as fuels.
     Alkanes release large amounts of energy upon combustion due to the breaking of C–H and C–C bonds releasing heat.


  20. Give reason why ethene can be polymerized but methane cannot.
     Ethene has a double bond that can open up to form long polymer chains; methane has only single bonds and cannot polymerize.


  21. Give reason why carboxylic acids react with metals to produce hydrogen gas.
     Carboxylic acids release H⁺ ions which react with metals to liberate H₂ gas.


  22. Give reason why alcohols can act as both weak acids and weak bases.
     The –OH group can donate a proton (acidic behavior) and the lone pair on oxygen can accept a proton (basic behavior).


  23. Give reason why alkanes have a tetrahedral geometry around carbon atoms.
     Each carbon in alkanes is sp³ hybridized, forming four sigma bonds arranged tetrahedrally with bond angles of about 109.5°.


  24. Give reason why fractional distillation is used to separate crude oil components.
     Different hydrocarbons have different boiling points, allowing them to be separated by controlled heating and condensation at different levels.


  25. Give reason why carboxylic acids smell unpleasant.
     Many carboxylic acids release volatile molecules with a sharp, pungent odor that is often unpleasant.


  26. Give reason why alkenes are called unsaturated hydrocarbons.
     They contain double bonds that can add more atoms, indicating they are not saturated with hydrogen.


  27. Give reason why substitution reactions in alkanes require UV light.
     UV light provides energy to break the halogen molecule’s bond, initiating the substitution reaction.


  28. Give reason why phenol is more acidic than alcohols.
     Phenol’s negative charge after losing H⁺ is stabilized by resonance over the aromatic ring, making it more acidic than alcohols.


  29. Give reason why alkenes undergo polymerization.
     The double bonds in alkenes can open up and link repeatedly, forming long-chain polymers.


  30. Give reason why ethanoic acid is soluble in water.
     The –COOH group can form hydrogen bonds with water, enabling good solubility.


  31. Give reason why tertiary butanol does not give a positive silver mirror test.
     Tertiary alcohols cannot be oxidized to aldehydes, which are required for the silver mirror test.


  32. Give reason why alkanes have lower densities than water.
     Alkanes have non-polar molecules with low intermolecular forces, resulting in lower density than water.


  33. Give reason why alkyne molecules have high acidity compared to alkanes.
     The hydrogen attached to the sp-hybridized carbon in alkynes is more acidic due to higher s-character and stronger attraction to the nucleus.


  34. Give reason why ethanol reacts with sodium but methane does not.
     Ethanol contains acidic hydrogen in the –OH group that reacts with sodium, while methane lacks acidic hydrogen.


  35. Give reason why carboxylic acids have higher melting points than corresponding alkanes.
     Carboxylic acids form hydrogen-bonded dimers which increase intermolecular attraction, raising melting points.


  36. Give reason why ethene is planar but ethane is tetrahedral.
     Ethene carbons are sp² hybridized leading to planar geometry, whereas ethane carbons are sp³ hybridized leading to tetrahedral shape.


  37. Give reason why alkenes have restricted rotation around the double bond.
     The pi bond formed by sideways overlap of p orbitals locks the double bond, preventing rotation.


  38. Give reason why alcohols can act as solvents for both polar and non-polar substances.
     Alcohols have a polar –OH group and a non-polar hydrocarbon chain, making them amphipathic solvents.


  39. Give reason why propene reacts with bromine in an addition reaction but propane does not.
     Propene contains a double bond which can react with bromine, whereas propane is saturated and does not react easily.


  40. Give reason why carboxylic acids turn blue litmus paper red.
     Carboxylic acids release H⁺ ions in solution, turning blue litmus red.


  41. Give reason why alkanes have low solubility in water but high solubility in organic solvents.
     Alkanes are non-polar and dissolve well in non-polar solvents, but poorly in polar solvents like water.


  42. Give reason why the molecular formula of alkynes is CₙH₂ₙ₋₂.
     Alkynes have a triple bond, reducing the number of hydrogen atoms by four compared to the corresponding alkane, resulting in the formula CₙH₂ₙ₋₂.


  43. Give reason why ethanol can be dehydrated to form ethene.
     In the presence of an acid catalyst and heat, ethanol loses water (dehydration) to form ethene.


  44. Give reason why alkenes are called unsaturated hydrocarbons.
     Alkenes contain one or more double bonds and thus have fewer hydrogen atoms than alkanes.


  45. Give reason why primary alcohols oxidize to aldehydes but tertiary alcohols do not oxidize easily.
     Primary alcohols have a hydrogen atom on the carbon bonded to –OH, allowing oxidation; tertiary alcohols lack this hydrogen.


  46. Give reason why carboxylic acids conduct electricity in aqueous solution.
     They ionize to produce H⁺ ions and carboxylate ions, allowing conduction of electricity.


  47. Give reason why alkenes have a planar structure around the double bond.
     The sp² hybridization leads to a trigonal planar geometry with 120° bond angles around each carbon in the double bond.


  48. Give reason why alkanes have low boiling points compared to alcohols of similar molecular weight.
     Alkanes only have weak van der Waals forces, whereas alcohols have strong hydrogen bonding.


  49. Give reason why the triple bond in alkynes is shorter and stronger than a double bond in alkenes.
     A triple bond consists of one sigma and two pi bonds, increasing bond strength and decreasing bond length.


  50. Give reason why carboxylic acids react with bases to form salts.
     Carboxylic acids donate H⁺ ions to bases, forming carboxylate salts and water.

Arrange the Words 

Case Studies

Case Study 1:
 A hydrocarbon ‘X’ with molecular formula C₂H₄ reacts with bromine water and the reddish-brown color disappears. On adding hydrogen in the presence of a catalyst, it forms C₂H₆. Identify ‘X’ and explain the reaction.

Answer:
 ‘X’ is ethene (C₂H₄), an alkene. It undergoes addition reaction with bromine (Br₂), decolorizing bromine water, indicating the presence of a double bond. Hydrogenation converts ethene into ethane (C₂H₆).

 

Case Study 2:
 A compound ‘Y’ (C₂H₆O) gives a sweet smell and burns with a blue flame. It reacts with sodium metal to release hydrogen gas. Identify ‘Y’ and explain the reactions.

Answer:
 ‘Y’ is ethanol (C₂H₅OH), an alcohol. The sweet smell is typical of ethanol. It burns with a blue flame showing combustion. Reaction with sodium releases hydrogen:
 2C₂H₅OH + 2Na → 2C₂H₅ONa + H₂↑

 

Case Study 3:
 A colorless liquid ‘Z’ with formula C₂H₄O₂ has a sour taste and reacts with sodium carbonate to release CO₂. Identify ‘Z’ and explain its reaction with sodium carbonate.

Answer:
 ‘Z’ is acetic acid (CH₃COOH), a carboxylic acid. It reacts with sodium carbonate:
 2CH₃COOH + Na₂CO₃ → 2CH₃COONa + CO₂↑ + H₂O

 

Case Study 4:
 A hydrocarbon ‘A’ (C₃H₆) gives a positive test with Baeyer’s reagent (cold alkaline KMnO₄) indicating the presence of an unsaturation. Identify ‘A’ and write the reaction involved.

Answer:
 ‘A’ is propene (C₃H₆), an alkene. It reacts with Baeyer’s reagent causing the purple color to disappear and a brown precipitate forms, indicating oxidation of the double bond:
 C₃H₆ + [O] → C₃H₆(OH)₂ (glycol)

 

Case Study 5:
 A hydrocarbon ‘B’ with formula C₂H₂ undergoes addition with hydrogen in presence of catalyst to give an alkane. Name ‘B’ and write the reaction.

Answer:
 ‘B’ is ethyne (C₂H₂), an alkyne. Hydrogenation converts it to ethane (C₂H₆):
 C₂H₂ + 2H₂ → C₂H₆

 

Case Study 6:
 A compound ‘C’ (C₃H₆O) has a functional group –OH but does not react with sodium bicarbonate. Identify the compound and justify.

Answer:
 ‘C’ is propanol (an alcohol). Alcohols do not react with sodium bicarbonate (NaHCO₃) because they are not acidic enough to release CO₂, unlike carboxylic acids.

 

Case Study 7:
 An unknown compound ‘D’ (C₄H₈) decolorizes bromine water and forms a polymer on heating. Identify the compound and explain the reaction.

Answer:
 ‘D’ is butene, an alkene. The double bond reacts with bromine water (addition reaction). Upon heating, polymerization occurs, forming polybutene.

 

Case Study 8:
 A saturated hydrocarbon ‘E’ (C₄H₁₀) undergoes substitution with chlorine in presence of UV light to form chlorobutane. Identify ‘E’ and type of reaction.

Answer:
 ‘E’ is butane, an alkane. The reaction with chlorine under UV light is a substitution (free radical) reaction:
 C₄H₁₀ + Cl₂ → C₄H₉Cl + HCl

 

Case Study 9:
 A compound ‘F’ with formula C₂H₆O shows a sharp smell and is miscible with water. On oxidation, it forms acetic acid. Name ‘F’ and describe its oxidation.

Answer:
 ‘F’ is ethanol (C₂H₅OH). Oxidation using acidified potassium dichromate:
 C₂H₅OH + [O] → CH₃COOH (acetic acid)

 

Case Study 10:
 A hydrocarbon ‘G’ with formula C₆H₆ is planar, unsaturated, and undergoes substitution rather than addition reactions. Identify ‘G’ and explain why.

Answer:
 ‘G’ is benzene (C₆H₆), an aromatic hydrocarbon. It undergoes substitution to maintain aromatic stability instead of addition reactions which would break the aromatic ring.

 

Case Study 11:
 A carboxylic acid ‘H’ reacts with ethanol in presence of concentrated sulfuric acid to form a sweet-smelling compound ‘I’. Name ‘H’, ‘I’ and the type of reaction.

Answer:
 ‘H’ is acetic acid (CH₃COOH). ‘I’ is ethyl acetate (CH₃COOCH₂CH₃), formed by esterification:
 CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O

 

Case Study 12:
 A compound ‘J’ (C₃H₈) burns with a yellow smoky flame and is a saturated hydrocarbon. Identify ‘J’ and explain the nature of the flame.

Answer:
 ‘J’ is propane (C₃H₈), an alkane. The yellow smoky flame is due to incomplete combustion producing soot (carbon particles).

 

Case Study 13:
 A compound ‘K’ has the formula C₄H₈ and shows cis-trans isomerism. Identify the class of compounds ‘K’ belongs to and explain cis-trans isomerism briefly.

Answer:
 ‘K’ is an alkene. Cis-trans isomerism arises due to restricted rotation around the C=C double bond, giving different spatial arrangements of substituents.

 

Case Study 14:
 A compound ‘L’ (C₂H₆O) is miscible with water and acts as a solvent in many organic reactions. Identify ‘L’ and explain why it is a good solvent.

Answer:
 ‘L’ is ethanol. It is polar and forms hydrogen bonds with water and many organic compounds, making it an excellent solvent.

 

Case Study 15:
 A hydrocarbon ‘M’ with formula C₅H₈ reacts with bromine but not with Baeyer’s reagent. Identify the likely class and name of ‘M’.

Answer:
 ‘M’ is likely an alkyne (pent-yne). Alkynes react with bromine but do not react with Baeyer’s reagent (cold KMnO₄), which oxidizes alkenes.

 

Case Study 16:
 A carboxylic acid ‘N’ gives a salt on reaction with sodium hydroxide and effervesces with sodium carbonate. Identify ‘N’ and write both reactions.

Answer:
 ‘N’ is a carboxylic acid like acetic acid.
 With NaOH: CH₃COOH + NaOH → CH₃COONa + H₂O
 With Na₂CO₃: 2CH₃COOH + Na₂CO₃ → 2CH₃COONa + CO₂↑ + H₂O

 

Case Study 17:
 A hydrocarbon ‘O’ is an alkane with formula C₆H₁₄. Draw its two isomers and name the reaction when it reacts with chlorine under UV light.

Answer:
 Two isomers: hexane (straight chain) and 2-methylpentane (branched). The reaction is substitution (free radical) with chlorine under UV light.

 

Case Study 18:
 A compound ‘P’ (C₂H₅OH) dehydrates on heating with concentrated H₂SO₄ to form ‘Q’. Identify ‘Q’ and write the reaction.

Answer:
 ‘Q’ is ethene (C₂H₄). Reaction:
 C₂H₅OH → C₂H₄ + H₂O (on heating with H₂SO₄)

 

Case Study 19:
 A hydrocarbon ‘R’ with formula C₃H₄ undergoes addition with hydrogen bromide to give C₃H₅Br. Name ‘R’ and type of reaction.

Answer:
 ‘R’ is propyne (C₃H₄), an alkyne. The reaction is electrophilic addition:
 C₃H₄ + HBr → C₃H₅Br

 

Case Study 20:
 A compound ‘S’ is an alcohol with formula C₄H₁₀O that gives a positive iodoform test. Identify ‘S’ and explain the test.

Answer:
 ‘S’ is either ethanol or a methyl ketone containing alcohol such as isopropanol. The iodoform test gives a yellow precipitate (CHI₃) indicating the presence of CH₃–CHOH group.

All Reactions

  1. Laboratory Preparation of Methane

CH₃COONa + NaOH → CH₄ + Na₂CO₃

 

  1. Laboratory Preparation of Ethane

C₂H₅COONa + NaOH → C₂H₆ + Na₂CO₃

 

  1. Reduction of Methyl Iodide

CH₃I + 2[H] → CH₄ + HI

 

  1. Reduction of Bromoethane

C₂H₅Br + 2[H] → C₂H₆ + HBr

 

  1. Complete Combustion of Methane

CH₄ + 2O₂ → CO₂ + 2H₂O

 

  1. Incomplete Combustion of Methane

2CH₄ + 3O₂ → 2CO + 4H₂O

 

  1. Substitution Reactions of Methane

CH₄ + Cl₂ → CH₃Cl + HCl
 CH₃Cl + Cl₂ → CH₂Cl₂ + HCl
 CH₂Cl₂ + Cl₂ → CHCl₃ + HCl
 CHCl₃ + Cl₂ → CCl₄ + HCl

 

  1. Substitution Reactions of Ethane

C₂H₆ + Cl₂ → C₂H₅Cl + HCl
 C₂H₅Cl + Cl₂ → C₂H₄Cl₂ + HCl
 C₂H₄Cl₂ + Cl₂ → C₂H₃Cl₃ + HCl
 C₂H₃Cl₃ + Cl₂ → C₂H₂Cl₄ + HCl
 C₂H₂Cl₄ + Cl₂ → C₂HCl₅ + HCl
 C₂HCl₅ + Cl₂ → C₂Cl₆ + HCl

 

  1. Addition of Hydrogen to Ethene (Hydrogenation)

CH₂=CH₂ + H₂ → CH₃–CH₃

 

  1. Addition of Bromine to Ethene

CH₂=CH₂ + Br₂ → CH₂Br–CH₂Br

 

  1. Addition of HBr to Ethene

CH₂=CH₂ + HBr → CH₃–CH₂Br

 

  1. Hydration of Ethene

CH₂=CH₂ + H₂O → CH₃–CH₂OH

 

  1. Oxidation of Ethene

CH₂=CH₂ + [O] + H₂O → CH₂OH–CH₂OH

 

  1. Oxidation of Ethane

2C₂H₆ + O₂ → 2C₂H₅OH

 

  1. Oxidation of Ethanol to Acetic Acid

C₂H₅OH + O₂ → CH₃COOH + H₂O

 

  1. Esterification Reaction

CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O

 

  1. Hydrolysis of Methyl Chloride

CH₃Cl + KOH (aq) → CH₃OH + KCl

 

  1. Dehydration of Ethanol

C₂H₅OH → CH₂=CH₂ + H₂O

 

  1. Polymerisation of Ethene

nCH₂=CH₂ → (–CH₂–CH₂–)ₙ

 

  1. Addition of Bromine to Ethyne

CH≡CH + Br₂ → CHBr=CHBr
 CHBr=CHBr + Br₂ → CHBr₂–CHBr₂

 

  1. Addition of Hydrogen to Ethyne

CH≡CH + 2H₂ → CH₃–CH₃

 

  1. Complete Combustion of Ethane

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

 

  1. Acetic Acid + Sodium Carbonate

2CH₃COOH + Na₂CO₃ → 2CH₃COONa + CO₂ + H₂O

 

  1. Acetic Acid + Sodium Hydroxide

CH₃COOH + NaOH → CH₃COONa + H₂O

 

  1. Acetic Acid + Sodium

2CH₃COOH + 2Na → 2CH₃COONa + H₂↑

 

  1. Acetic Acid + Ethanol (Esterification)

CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O

 

  1. Ethene + Chlorine

CH₂=CH₂ + Cl₂ → CH₂Cl–CH₂Cl

 

  1. Ethene + Hydrogen Bromide

CH₂=CH₂ + HBr → CH₃–CH₂Br

 

  1. Ethene + Water

CH₂=CH₂ + H₂O → CH₃–CH₂OH

 

  1. Ethene + Alkaline KMnO₄

CH₂=CH₂ + [O] + H₂O → CH₂OH–CH₂OH

 

  1. Ethyne + Hydrogen

CH≡CH + 2H₂ → CH₃–CH₃

 

  1. Ethyne + Bromine

CH≡CH + Br₂ → CHBr=CHBr
 CHBr=CHBr + Br₂ → CHBr₂–CHBr₂

 

  1. Ethyne + Hydrogen Bromide

CH≡CH + 2HBr → CH₂Br–CH₂Br

 

  1. Ethyne + Water

CH≡CH + H₂O → CH₃CHO


Other Reactions:

  1. Ethyl alcohol + Acetic acid
    Product: Ethyl ethanoate (ester)
     Reaction: CH₃COOH + C₂H₅OH → CH₃COOC₂H₅ + H₂O





ICSE Grade 10

3500/-
  • All Subjects
  • Free Study Material
  • MCQ Tests
  • Theory Tests
  • Assignments
Register

Find out free resources that you need.

ICSE

Grade 8

Grade 9

Grade 10

CBSE

Grade 8

Grade 9

Grade 10

Subjects we teach

“Arise, awake, and learn by approaching the excellent teachers”

Shiksha Marg 108 gives you all free resources to ensure you get the best results. Get ready for you ICSE and CBSE exams!.

ENROLL
ENROLL
error:
Scroll to Top