Daily Olympiad: Chemistry - Hydrocarbons [20260601]

Solution

Correct: B

Cyclobutene is a cyclic diene. Substituents on adjacent carbons can lead to geometric (cis/trans) isomerism due to ring rigidity preventing free rotation. Structural isomerism could exist if substituents vary positions, but in adjacent positions, geometric isomerism dominates.

Solution

Correct: D

Numbering the chain to give the double bond the lowest possible number (1-pentene) is prioritized. Substituent number (Br at C-4) becomes less critical than functional group position. Hence, correct name: 4-Bromo-1-pentene.

Solution

Correct: A

E1 mechanism involves carbocation intermediate. Tertiary alkyl halides form stable carbocations, favoring E1. Primary alkyl halides undergo E2. So (CH₃)₃CCH₂Br forms (CH₃)₃C+ a very stable carbocation, leading to major product.