CBSE Class 11 Chemistry Hydrocarbons MCQs


Question: Which of the following fuel cause the least pollution ?

  • a) LPG
  • b) CNG
  • c) Petrol
  • d) Kerosene

Answer: LPG


Question: LPG mainly contains

  • a) butane
  • b) ethane
  • c) methane
  • d) ethyne

Answer: butane


Question: Which of the following gas is find in coal mines and marshy places?

  • a) Methane
  • b) Ethane
  • c) Propane
  • d) Benzene

Answer: Methane


Question: Two adjacent members of a homologous series have

  • a) All the above
  • b) same general method of preparation
  • c) a different of 14 amu in molecular mass
  • d) a difference of CH2 in their structure

Answer: All the above


Question: Methane, ethane and propane are said to form a homologous series because all are

  • a) differ from each other by a CH2 group
  • b) aliphatic compounds
  • c) saturated compounds
  • d) hydrocarbons

Answer: differ from each other by a CH2 group


Question: The number of primary, secondary and tertiary carbons in 3, 4-dimethylheptane are respectively

  • a) 4, 3 and 2
  • b) 4, 2 and 3
  • c) 2, 3 and 4
  • d) 3, 4 and 2

Answer: 4, 3 and 2


Question: Which of the following statements is false for isopentane

  • a) It has a carbon which is not bonded to hydrogen
  • b) It has one CH group
  • c) It has three CH3 groups
  • d) It has one CH2 group

Answer: It has a carbon which is not bonded to hydrogen


Question: How many isomers are possible for the C5H12 ?

  • a) 3
  • b) 5
  • c) 2
  • d) 4

Answer: 3


Question: The number of 4° carbon atoms in 2,2,4,4-tetramethyl pentane is –

  • a) 2
  • b) 4
  • c) 1
  • d) 3

Answer: 2


Question: Which one of the following cannot be prepared by Wurtz reaction ?

  • a) CH4
  • b) C2H6
  • c) Both
  • d) None of these

Answer: CH4


Question: Pure methane can be produced by

  • a) Soda-lime decarboxylation
  • b) Reduction with H2
  • c) Kolbe’s electrolytic method
  • d) Wurtz reaction

Answer: Soda-lime decarboxylation


More Questions......................


Question: Sodium salts of carboxylic acids on heating with soda lime give alkanes containing _______ than the carboxylic acid

  • a) one carbon less
  • b) one carbon more
  • c) two carbon less
  • d) All of these

Answer: one carbon less


Question: Which one of the following has the least boiling point?

  • a) 2, 2– dimethylpropane
  • b) 2-methylpropane
  • c) n-butane
  • d) n-pentane

Answer: 2, 2– dimethylpropane


Question: Which one of the following has highest boiling point?

  • a) n-Octane
  • b) Iso-octan
  • c) 2,2 dimethyl pentane
  • d) All have equal values

Answer: n-Octane


Question: In the free radical chlorination of methane, the chain initiating step involves the formation of

  • a) chlorine free radical
  • b) hydrogen chloride
  • c) methyl radical
  • d) chloromethyl radical.

Answer: chlorine free radical


Question: Which one of the following gives only one monochloro derivative?

  • a) neo-pentane
  • b) 2-methylpentane
  • c) n-hexane
  • d) 2, 3-dimethylpentane

Answer: neo-pentane


Question: Photochemical halogenation of alkane is an example of

  • a) free radical substitution
  • b) nucleophilic substitution
  • c) electrophilic addition
  • d) electrophilic substitution

Answer: free radical substitution


Question: 2-Methylbutane on reacting with bromine in the presence of sunlight gives mainly

  • a) 2-bromo-2-methylbutane
  • b) 1-bromo-2-methylbutane
  • c) 2-bromo-3-methylbutane
  • d) 1-bromo-3-methylbutane

Answer: 2-bromo-2-methylbutane


Question: Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by

  • a) cracking
  • b) distillation under reduced pressure
  • c) hydrolysis
  • d) oxidation

Answer: cracking


Question: n-Hexane isomerises in presence of anhydrous aluminium chloride and hydrogen chloride gas to give

  • a) Both
  • b) 2-Methyl pentane
  • c) 3-Methyl pentane
  • d) None of these

Answer: Both


Question: How many conformations are possible for ethane ?

  • a) infinite
  • b) 2
  • c) 3
  • d) one

Answer: infinite




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