JEE Chemistry Hydrocarbons MCQs Set A

Question. Which of the following fuel cause the least pollution ?
(a) LPG
(b) CNG
(c) Petrol
(d) Kerosene

Answer: A

Question. LPG mainly contains
(a) butane
(b) ethane
(c) ethyne
(d) methane

Answer: A

Question. Natural gas is a mixture of
(a) CH₄ + C₂H₆ + C₃H₈
(b) CO + H₂ + CH₄
(c) CO + H₂
(d) None of these

Answer: A

Question. Which of the following gas is find in coal mines and marshy places?
(a) Methane
(b) Benzene
(c) Ethane
(d) Propane

Answer: A

Question. Which of the following represents the correct general formula of alkanes ?
(a) C_nH2_{n + 2}
(b) C_nH_n
(c) C_nH_2n
(d) C_nH_{2n – 2}

Answer: A

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: A

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: A

Question. Which of the following does not belong to the same homologous series?
(a) C₄H₈
(b) C₂H₆
(c) CH₄
(d) C₃H₈

Answer: A

Question. The number of chain isomers possible for the hydrocarbon C₅H₁₂ is
(a) 3
(b) 1
(c) 2
(d) 4

Answer: A

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: A

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 one CH₂ group
(d) It has three CH₃ groups

Answer: A

Question. Molecular formula of which of the following alkane can exist in more than one structure ?
(a) C₄H₁₀
(b) C₂H₆
(c) CH₄
(d) None of these

Answer: A

Question. How many isomers are possible for the C₅H₁₂ ?
(a) 3
(b) 5
(c) 2
(d) 4

Answer: A

Question. The number of 4° carbon atoms in 2,2,4,4-tetramethyl pentane is –
(a) 2
(b) 4
(c) 1
(d) 3

Answer: A

Question. Which one of the following cannot be prepared by Wurtz reaction ?
(a) CH₄
(b) C₃H₈
(c) C₂H₆
(d) C₄H₁₀

Answer: A

Question. Pure methane can be produced by
(a) Soda-lime decarboxylation
(b) Reduction with H₂
(c) Kolbe’s electrolytic method
(d) Wurtz reaction

Answer: A

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) None of these

Answer: A

Question. Which one of the following has the least boiling point?
(a) 2, 2– dimethylpropane
(b) n-butane
(c) n-pentane
(d) 2-methylpropane

Answer: A

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: A

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: A

Question. Photochemical halogenation of alkane is an example of
(a) free radical substitution
(b) nucleophilic substitution
(c) electrophilic addition
(d) electrophilic substitution

Answer: A

Question. 2-Methylbutane on reacting with bromine in the presence of sunlight gives mainly
(a) 2-bromo-2-methylbutane
(b) 2-bromo-3-methylbutane
(c) 1-bromo-3-methylbutane
(d) 1-bromo-2-methylbutane

Answer: A

Question. Aromatisation of n-hexane gives
(a) benzene
(b) toluene
(c) cyclohexane
(d) cycloheptane

Answer: A

Question. Liquid hydrocarbons can be converted to a mixture of gaseous hydrocarbons by
(a) cracking
(b) oxidation
(c) distillation under reduced pressure
(d) hydrolysis

Answer: A

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: A

Question. How many conformations are possible for ethane ?
(a) infinite
(b) 2
(c) 3
(d) one

Answer: A

Question. Spatial arrangements of atoms which can be converted into one another by rotation around a C–C single bond are called
(a) Conformers
(b) Tautomers
(c) Stereoisomers
(d) Optical isomers

Answer: A

Question. The restricted rotation about carbon-carbon double bond in 2- butene is due to
(a) sideways overlap of two p-orbitals
(b) overlap of one p-and one sp²-hybridized orbitals
(c) overlap of two sp²-hybridized orbitals
(d) overlap of one s- and one sp²-hybridized orbitals

Answer: A

Question. Bond angle in alkenes is equal to
(a) 120°
(b) 180°
(c) 109°28'
(d) 60°

Answer: A

Question. The molecular formula of a compound in which double bond is present between C & C
(a) C_nH_2n
(b) C_nH_{2n + 2}
(c) C_nH_2n–2
(d) None of these

Answer: A

Question. Reaction of hydrogen bromide with propene in the absence of peroxide is a/an
(a) electrophilic addition
(b) electrophilic substitution
(c) nucleophilic addition
(d) free radical addition

Answer: A

Question. Which of the following represents the correct IUPAC name of the compound
CH₂ = CH – CH₂ Cl?
(a) 3- chloro-1- propene
(b) Allyl chloride
(c) Vinyl chloride
(d) None of these

Answer: A

Question. The alkene that exhibits geometrical isomerism is
(a) 2-butene
(b) propene
(c) 2- methyl propene
(d) 2- methyl -2- butene

Answer: A

Question. Which one of the following exhibits geometrical isomerism?
(a) Both
(b) 1, 2-dibromopropene
(c) 2, 3-dibromobut-2-ene
(d) None of these

Answer: A

Question. The compounds CH₃CH == CHCH₃ and CH₃CH₂CH == CH₂
(a) are position isomers
(b) are tautomers
(c) exist together in dynamic equilibrium
(d) None of these

Answer: A

Question. The total number of isomers for C₄H₈ is
(a) 6
(b) 8
(c) 5
(d) 7

Answer: A

Question. Consider the following statements : A hydrocarbon of molecular formula C₅H₁₀ is a
I. monosubstituted alkene
II. disubstituted alkene
III. trisubstituted alkene
Which of the following statement(s) is(are) correct?
(a) I, II and III
(b) I and II
(c) II and III
(d) I and III

Answer: A

Question. Hex-2-ene and 2-methylpent-2-ene exhibit
(a) chain isomerism
(b) geometrical isomerism
(c) position isomerism
(d) optical isomerism

Answer: A

Question.  Ethyl bromide gives ethylene when reacted with
(a) alcoholic KOH
(b) dilute H₂SO₄
(c) ethyl alcohol
(d) aqueous KOH

Answer: A

Question. By which reaction ethene is obtained from ethyne
(a) hydrogenation
(b) oxidation
(c) polymerisation
(d) dehydrogenation

Answer: A

Question. Ethyl alcohol is heated with conc. H₂SO₄ . The product formed is
(a) C₂H₄
(b) C₂H₂
(c) C₂H₆
(d) None of these

Answer: A

Question. Alcoholic solution of KOH is used for
(a) Dehydrohalogenation
(b) Dehalogenation
(c) Dehydrogenation
(d) Dehydration

Answer: A

Question.  Paraffins are soluble in
(a) Benzene
(b) Sea water
(c) Distilled water
(d) Methanol

Answer: A

Question. When hydrochloric acid gas is treated with propene in presence of benzoyl peroxide, it gives
(a) 2-Chloropropane
(b) No reaction
(c) Allyl chloride
(d) n-Propyl chloride

Answer: A

Question. "The addition of unsymmetrical reagents to unsymmetrical alkenes occurs in such a way that the negative part of the addendum goes to that carbon atom of the double bond which carries lesser number of hydrogen atoms" is called by
(a) Markownikoff's rule
(b) Anti-Saytzeff rule
(c) Saytzeff rule
(d) Kharasch effect

Answer: A

Question. When one mole of an alkene on ozonolysis produces 2 moles of propanone, the alkene is
(a) 2, 3-dimethyl-2-butene
(b) 2, 3-dimethyl-2-pentene
(c) 2, 3-dimethyl-1-butene
(d) 3-methyl-1-butene

Answer: A

Question. The major product formed when 2-bromobutane is treated with alcoholic KOH is
(a) Trans-2-butene
(b) 1-Butene
(c) 2-Butanol
(d) 1-Butanol

Answer: A

Question. Reaction of HBr with propene in the presence of peroxide give
(a) n-propyl bromide
(b) 3-bromo propane
(c) isopropyl bromide
(d) allyl bromide

Answer: A

Question. Butene-1 may be converted to butane by reaction with
(a) Pd/H₂
(b) Sn – HCl
(c) Zn – Hg
(d) Zn – HCl

Answer: A

Question. Alkenes usually show which type of reaction
(a) addition
(b) elimination
(c) substitution
(d) superposition

Answer: A

Question.  A reagent used to test unsaturation in alkene is
(a) solution of Br₂ in CCl₄
(b) conc. H₂SO₄
(c) ammonical AgNO₃
(d) ammonical Cu₂Cl₂

Answer: A

Question. Polythene is a resin obtained by polymerisation of
(a) Ethylene
(b) Ethyne
(c) Methane
(d) None of these

Answer: A

Question. Ethyl hydrogen sulphate is obtained by reaction of H₂SO₄ on
(a) Ethylene
(b) Ethyl chloride
(c) Ethane

Answer: A

Question. The negative part of an addendum adds on to the carbon atom joined to the least number of hydrogen atoms. This statement is called
(a) Markownikoff’s rule
(b) Thiele’s theory
(c) Peroxide effect
(d) Baeyer’s strain theory

Answer: A

Question.  Which of the following compounds does not follow Markownikoff’s law ?
(a) CH₃CH = CHCH₃
(b) CH₃CH = CH₂
(c) CH₂CHCl
(d) None of these

Answer: A

Question. One mole of a symmetrical alkene on ozonolysis gives two moles of an aldehyde having a molecular mass of 44 u. The alkene is
(a) 2-butene
(b) propene
(c) 1-butene
(d) ethene

Answer: A

Question. The alkene that will give the same product with HBr in the absence as well as in the presence of peroxide is
(a) 2-butene
(b) propene
(c) 1-butene
(d) 1-hexene

Answer: A

Question. Ethylene reacts with alkaline KMnO₄ to form
(a) Glycol
(b) HCHO
(c) Oxalic acid
(d) Ethyl alcohol

Answer: A

Question. Ethene when treated with Br₂ in the presence of CCl₄ which compound is formed
(a) 1-bromo-2-chloroethane
(b) 1, 2-dibromoethane
(c) 1, 1, 1-tribromoethane
(d) None of these

Answer: A

Question. The test for unsaturation is confirmed by the decolourisation of which of the following
(a) Bromine water
(b) Iodine water
(c) CuSO₄ solution
(d) All of these

Answer: A

Question. Isopropyl alcohol is obtained by reacting which of the following alkenes with conc. H₂SO₄ and H₂O
(a) Propylene
(b) Isoprene
(c) Ethylene
(d) 2-methyl propene

Answer: A

Question. In the presence of peroxide, hydrogen chloride and hydrogen iodide do not give anti-Markownikov’s addition to alkenes because
(a) One of the steps is endothermic in both the cases
(b) All the steps are exothermic in both the cases
(c) One is oxidising and the other is reducing
(d) None of these

Answer: A