21. The main reaction alkanes undergo with halogens is:

• A) Hydrogenation
• B) Halogenation
• C) Hydration
• D) Polymerization
• Answer: B

22. Which type of isomerism is exhibited by alkanes?

• A) Geometrical isomerism
• B) Chain isomerism
• C) Optical isomerism
• D) Positional isomerism
• Answer: B

23. Which of the following is the molecular formula of butane?

• A) C₄H₆
• B) C₄H₈
• C) C₄H₁₀
• D) C₄H₁₂
• Answer: C

24. What is the main product of the combustion of alkanes?

• A) Carbon dioxide and water
• B) Hydrogen gas
• C) Methanol
• D) Ethanol
• Answer: A

25. Alkanes are generally:

• A) Soluble in water
• B) Soluble in organic solvents
• C) React with acids
• D) Polar molecules
• Answer: B

26. Which of the following is the major constituent of natural gas?

• A) Ethane
• B) Propane
• C) Methane
• D) Butane
• Answer: C

27. The bond angles in alkanes are approximately:

• A) 120°
• B) 180°
• C) 90°
• D) 109.5°
• Answer: D

28. Which method is commonly used to prepare alkanes in the laboratory?

• A) Wurtz reaction
• B) Hydration of alkenes
• C) Dehydrohalogenation
• D) Hydrolysis of esters
• Answer: A

29. Which of the following is the IUPAC name of CH₃CH₂CH₃?

• A) Propene
• B) Propane
• C) Propyne
• D) Ethane
• Answer: B

30. What is the major product of the halogenation of alkanes?

• A) Alkyl halides
• B) Alcohols
• C) Ethers
• D) Ketones
• Answer: A