Question

Compound A $\left(C_7{H}_{15}Br\right)$ is not a primary alkyl bromide. It yield a single alkene (compound B) on being heated with sodium ethoxide in ethanol. Hydrogenation of compound B yield $2,4-$dimethylpentane. Identify compounds A and B.

• A. 3-Bromo-2,4-dimethylpentane and 2,4-Dimethylpent-2-ene
• B. 2-bromo-2,4-dimethylhexane and 2,4-dimethylhex-2-ene
• C. 3-bromo-2,4-dimethylhexane and 2,3-dimethylhex-2-ene
• D. None of these

Answer 1

Answer: (A)

3-Bromo-2,4-dimethylpentane and 2,4-Dimethylpent-2-ene

Dehydrobromination of 3-bromo-2,4-dimethylpentane

(molecular formula: $C_7{H}_{15}Br$) by heating with sodium ethoxide in ethanol gives a 2,4-dimethylpent-2-ene having molecular formula $C_7{H}_{14}$;. This on catalytic hydrogenation form 2,4-dimethylpentane
(molecular formula: $C_7{H}_{16}$).