CBSE Class 11 Chemistry Hydrocarbons MCQs Set 03

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

Question: Product fo1med on electro! ysis of potassium salt of fumaric and maleic acid is 
a) ethane
b) ethene
c) ethyne
d) methane
Answer: c

Question: The pair of electrons in the given carbanion,CH₃C C –, is present in which of the followingorbitals?
a) sp²
b) sp
c) 2p
d) sp³
Answer: b

Question: Which of the following organic compounds hassame hybridization as its combustion product (CO₂)?
a) Ethane
b) Ethyne
c) Ethene
d) Ethanol
Answer: b

Question: Hydrocarbon (A) reacts with bromine by substitution to form an alkyl bromide which by Wurtz reaction is converted to gaseous hydrocarbon containing less than four carbon atoms. (A) is
a) CH CH
b) CH₂ CH₂
c) CH₃ — CH₃
d) CH₄ 
Answer: d

Question: With respect to the conformers of ethane, which of the following statements is true?
a) Bond angle changes but bond length remains ame.
b) Both bond angle and bond length change.
c) Both bond angle and bond length remain same.
d) Bond angle remains same but bond length changes.
Answer: c

Question: Which of the following has zero dipole moment?
a) 1-Butene
b) 2-Methyl-1-propene
c) cis-2-Butene
d) trans-2-Butene 
Answer: d

Question: One of the following which does not observe the anti-Markownikoff’s addition of HBr, is
a) pent-2-ene
b) propene
c) but-2-ene
d) but-1-ene. 
Answer: c

Question: Which one of these is not compatible with arenes?
a) Electrophilic additions
b) Delocalisation of p-electrons
c) Greater stability
d) Resonance
Answer: a

Question: The cylindrical shape of an alkyne is due to
a) two sigma C – C and one p C – C bonds
b) one sigma C – C and two p C – C bonds
c) three sigma C – C bonds
d) three p C – C bonds.
Answer: b

Question: Acetylenic hydrogens are acidic because
a) sigma electron density of C – H bond in acetylene is nearer to carbon, which has 50%s-character 
b) acetylene has only open hydrogen in eachcarbon 
c) acetylene contains least number of hydrogens among the possible hydrocarbons having twocarbons 
d) acetylene belongs to the class of alkynes with molecular formula, CnH₂n^–2.
Answer: a

Question: Geometrical isomers differ in
a) position of functional group
b) position of atoms
c) spatial arrangement of atoms
d) length of carbon chain. 
Answer: c

Question: The correct order of reactivity towards theelectrophilic substitution of the compounds aniline (I), benzene (II) and nitrobenzene (III) is
a) III > II > I
b) II > III > I
c) I < II > III
d) I > II > III
Answer: d

Question: Which of the following is used as an antiknocking material?
a) Glyoxal
b) Freon
c) T.E.L.
d) Ethyl alcohol 
Answer: c

Question: When acetylene is passed through dil. H₂SO₄ in thepresence of HgSO₄, the compound formed is
a) acetic acid
b) ketone
c) ether
d) acetaldehyde.
Answer: d

Question: The reactive species in the nitration of benzene is
a) NO₃
b) HNO₃
c) NO₂ ⁺
d) NO₂^–
Answer: c

Question: The oxidation of benzene by V₂O₅ in the presence of air produces
a) maleic anhydride
b) benzoic acid
c) benzaldehyde
d) benzoic anhydride.
Answer: a

Question: Some meta-directing substituents in aromaticsubstitution are given. Which one is most deactivating?
a) — COOH
b) — NO₂
c) — C≡ N
d) — SO₃H
Answer: b

Question: 2-Butene shows geometrical isomerism due to
a) restricted rotation about double bond
b) free rotation about double bond
c) free rotation about single bond
d) chiral carbon. 
Answer: a

Question: In the commercial gasolines, the type ofhydrocarbons which are more desirable is
a) linear unsaturated hydrocarbon
b) toluene
c) branched hydrocarbon
d) straight-chain hydrocarbon. 
Answer: c

Question: Among the following compounds the one that is most reactive towards electrophilic nitration is
a) benzoic acid
b) nitrobenzene
c) toluene
d) benzene.
Answer: c

Question: Benzene reacts with CH₃Cl in the presence of anhydrous AlCl₃ to form
a) chlorobenzene
b) benzyl chloride
c) xylene
d) toluene. 
Answer: d

Question: Which of the following reagents will be able to distinguish between 1-butyne and 2-butyne?
a) NaNH₂
b) HCl
c) O₂
d) Br₂
Answer: a

Question: Nitrobenzene can be prepared from benzene byusing a mixture of conc. HNO₃ and conc. H₂SO₄. In the mixture, nitric acid acts as a/an
a) acid
b) base
c) catalyst
d) reducing agent.
Answer: b

Question: Electrophile in the case of chlorination of benzene in the presence of FeCl₃ is
a) Cl
b) FeCl₃
c) Cl⁺
d) Cl^–
Answer: c

Question: Which of the following compounds will not undergo Friedel-Crafts reaction easily?
a) Nitrobenzene
b) Toluene
c) Cumene
d) Xylene
Answer: a

Question: Considering the state of hybridization of carbon atoms, find out the molecule among the following which is linear?
a) CH₃ — CH= CH — CH₃
b) CH₃ — C≡ C — CH₃
c) CH₂ CH — CH₂ — C≡ CH
d) CH₃ — CH₂ — CH₂ — CH₃
Answer: b

Question: Which is maximum stable?
a) 1-Butene
b) cis-2-Butene
c) trans-2-Butene
d) All have same stability. 
Answer: c

Question: Which is the most suitable reagent among the following to distinguish compound (3) from rest of the compounds?
(1) CH₃ – C C – CH₃
(2) CH₃ – CH₂ – CH2 – CH₃
(3) CH₃ – CH2C≡ CH
(4) CH₃ – CH= CH₂
a) Bromine in carbon tetrachloride
b) Bromine in acetic acid
c) Alk. KMnO₄
d) Ammoniacal silver nitrate
Answer: d

Question: The order of decreasing reactivity towards an electrophilic reagent, for the following would be
(i) benzene                 (ii) toluene
(iii) chlorobenzene     (iv) phenol
a) (ii) > (iv) > (i) > (iii)
b) (iv) > (iii) > (ii) > (i)
c) (iv) > (ii) > (i) > (iii)
d) (i) > (ii) > (iii) > (iv)
Answer: c