One of the products of the following reaction is $P$. Structure of $P$ is

$p$-Cresol reacts with chloroform in an alkaline medium to give compound $A$,which on addition of hydrogen cyanide forms compound $Y$. Acidic hydrolysis of $Y$ yields a chiral carboxylic acid. What is the structure of the carboxylic acid?

$C_{7}H_{10}O$ reacts with $CH_{3}MgBr$ to give a compound $C_{8}H_{12}O$ which gives a positive iodoform test. Identify the structure of $A$.

One mole of an organic compound requires $0.5$ mole of oxygen to produce an acid. The compound may be

Identify the product $A$ in the following reaction:
$\text{Substrate} \xrightarrow{MnO_2} A$
(The substrate is a benzene ring with a $-OH$ group,a $-COOH$ group,and a $-CH(CH_2CH_3)CHO$ group attached to it.)

The major product of the following reaction is