Alkene MCQs

Alkenes are unsaturated hydrocarbons that contain at least one carbon-carbon double bond. Their general formula is CₙH₂ₙ. Alkenes are also referred to as olefins because of their tendency to form oils. Due to the presence of a weak pi bond and loosely held electrons, alkenes are easily attacked by electrophilic reagents.

Cis-trans isomerism in alkenes is due to

(a) chiral carbon
(b) free rotation about single bond
(c) free rotation about the double bond
(d) restricted rotation about the double bond

Baeyer’s reagent is used to detect

(a) glucose
(b) double bonds
(c) oxidation
(d) reduction

Which of the following will form 2 acetaldehyde molecules on ozonolysis?

(a) 1-pentene
(b) 2-pentene
(c) 1-butene
(d) 2-butene

Which of the following reagents will form 1-propanol from propene?

(a) B₂H₆, H₂O₂, OH^–
(b) Aq. KOH
(c) H₂O, H₂SO₄
(d) Hg(OAc)₂, NaBH₄/H₂O

Geometrical isomerism is exhibited by

(a) 2-Butene
(b) 2-Butyne
(c) 2-Butenol
(d) Butanol

Which of the following reactions is common in alkenes?

(a) Addition
(b) Elimination
(c) Substitution
(d) Superposition

Ethylene bromide on treatment with Zn gives

(a) Alkyne
(b) Alkene
(c) Alkane
(d) All of the above

Find the alkene with maximum stability

(a) cis-2-Butene
(b) trans-2-Butene
(c) 1-Butene
(d) All have the same stability

When propene reacts with HBr in the presence of peroxide, it gives rise to

(a) allyl bromide
(b) isopropyl bromide
(c) n-propyl bromide
(d) 3-bromopropane

Which of the following compounds react most readily with Br(g)?

(a) C₂H₂
(b) C₃H₆
(c) C₂H₄
(d) C₄H₁₀