Which of the following reagent$(s)$ is/are used for the given conversion?

Write down functional isomers of a carbonyl compound with molecular formula $C_3H_6O$. Which isomer will react faster with $HCN$ and why? Explain the mechanism of the reaction also. Will the reaction lead to the completion with the conversion of whole reactant into product at reaction conditions? If a strong acid is added to the reaction mixture what will be the effect on concentration of the product and why?

Which reagent is suitable for the following transformation?

In the following reaction sequence,the product $D$ is:
$CH_3COOH$ $\xrightarrow{SOCl_2} A$ $\xrightarrow[AlCl_3]{C_6H_6} B$ $\xrightarrow{HCN} C$ $\xrightarrow{H_2O} D$

The reaction shown in the image proceeds via which mechanism?

Statement $I$: Aldehyde on reaction with $HCN$ gives Cyanohydrin.
Statement $II$: Cyanohydrin is a compound which consists of hydroxy and cyano groups on the same carbon.
Choose the correct answer from the following with reference to above statements.