Question

Reaction of Grignard reagent, $C_2{H}_{5}MgBr$ with $C_8{H}_{8}O$ followed by hydrolysis gives compound ''A'' which reacts instantly with Lucas reagent to give compound B, $C_{10}{H}_{13}Cl$.
Compound (B) is

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• A.
• B.
• C.
• D.

Answer 1

The correct option is D

The reaction of alcohol with Lucas reagent $(\text{conc.}HCl+\text{anhyd.}ZnC{l}_2)$ is mostly $S_{N}1$ reaction and the rate of reaction is directly proportional to the stability of carbocation formed in the reaction.
Since, $3^o$ alcohol forms $3^o$ carbocation (most stable) hence, it will react fastest by $S_{N}1$ reaction to give tertiary halide.

Thus, compound (A) is a tertiary alcohol.
Since $C_2{H}_{5}MgBr$ with $C_8{H}_{8}O$ followed by hydrolysis gives tertiary alcohol, the starting compound is a keto compound.
Hence, with help of molecular formula, the above reaction is given below:


Hence, option (a) is correct.