$A$ methyl group attached to a benzene ring can be oxidized to a carboxyl group by reacting with:

Acid $D$ formed in the reaction sequence is:

The reaction of toluene with acidic $KMnO_4$ gives ..........

Identify the product $C$ in the following reaction sequence:
$CH_3CN$ $\xrightarrow{Na/C_2H_5OH} A$ $\xrightarrow{HNO_2} B$ $\xrightarrow{Cr_2O_7^{2-}} C$

In the reaction sequence,$C_2H_5Cl + KCN$ $\xrightarrow{C_2H_5OH} X$ $\xrightarrow{H_3O^{\oplus}, \Delta} Y$. What is the molecular formula of $Y$?

Consider the following reactions. From these reactions,which reaction will give carboxylic acid as a major product?
$(A)$ $R-C \equiv N \xrightarrow[(i) H^{+}/H_2O]{\text{mild condition}} R-CONH_2$
$(B)$ $R-MgX \xrightarrow[(ii) H_3O^{+}]{\text{(i) } CO_2} R-COOH$
$(C)$ $R-C \equiv N \xrightarrow[(ii) H_3O^{+}]{\text{(i) } SnCl_2/HCl} R-CHO$
$(D)$ $R-CH_2-OH \xrightarrow{PCC} R-CHO$
$(E)$ $\text{Benzoyl chloride} \xrightarrow[(ii) Br_2/H_2O]{\text{(i) } H_2/Pd-BaSO_4} \text{Benzoic acid}$
Choose the correct answer from the options given below: