Question

A compound ${}^{\prime }{A}^{\prime }$ having the molecular formula $C+5H_{12}O$, on oxidation gives a compound ${}^{\prime }{B}^{\prime }$ with molecular formula $C_5{H}_{10}O$. Compound ${}^{\prime }{B}^{\prime }$ gave a $2,4-$dinitrophenylhydrazine derivative but did not answer haloform test or silver mirror test. The structure of compound ${}^{\prime }{A}^{\prime }$ is

• A.
• B.
• C.
• D.

Answer 1

Answer: (C)

Since $(B)$ on reaction with $2,4-DNP$ forms a derivative, it implies that $(B)$ has group
$(B)$ gives $-ve$ Tollens’ test, hence it is not an aldehyde, but it is a ketone.
$(B)$ gives $-ve$ haloform test, thus it is not a methyl ketone.
$(B)$ is formed from the oxidation of $(A)$, thus $(A)$ is a $2^{\circ }$ alcohol, and among the given options,
$(A)$ is :
and $\therefore (B)$ is