Question

An organic compound $X$ is oxidized by using acidified $K_{2} C r_{2} O_{7} .$ The product obtained reacts with phenyl hydrazine, but does not answer silver mirror test. The possible structure of $X$ is

• A. $CH _{3} COCH _{3}$
• B. $\left( CH _{3}\right)_{2} CHOH$
• C. $CH _{3} CHO$
• D. $CH _{3} CH _{2} OH$

Answer 1

Answer: (B)

Secondary alcohols on oxidation with $K _{2} Cr _{2} O _{7}$ form ketone, ketones react with phenyl hydrazine to form hydrazone but does not react with Tollen's reagent.
$H_{3}C - \underset{\overset{|}{CH_{3}}}{\overset{\underset{|}{H}}{C}} -OH \ce{->[{K_{2}Cr_{2}O_{7}}][{H_{2}SO_{4}}]} CH_{3} - \underset{\overset{|}{CH_{3}}}{C} = O +H_{2}O$