Question

Which one of the following reactions will not yield propionic acid?

• A. $CH _{3} CH _{2} COCH _{3}+ OI ^{-} / H _{3} O ^{+}$
• B. $CH _{3} CH _{2} CH _{3}+ KMnO _{4}$ (Heat), $OH^- / H _{3} O ^{+}$
• C. $CH _{3} CH _{2} CCl _{3}+ OH ^{-} / H _{3} O ^{+}$
• D. $CH _{3} CH _{2} CH _{2} Br + Mg , CO _{2}$ dry ether/ $H _{3} O ^{+}$

Answer 1

Answer: (D)

All gives propanoic acid as product but option $4$ gives butanoic as product $CH_3CH_2CH_2Br \xrightarrow[\text{Dry ether}]{Mg} CH_3CH_2CH_2MgBr \xrightarrow{CO_2} $ $CH_3 - CH_2 - CH_2 - \overset{\underset{||}{O}}{C} - O MgBr \xrightarrow{H_3O^+} \underset{\text{Butanoic acid}}{CH_3 - CH_2 - CH_2 - \overset{\underset{||}{O}}{C} - OH}$