$A$ carbonyl compound reacts with hydrogen cyanide $(HCN)$ to form cyanohydrin,which on hydrolysis forms a racemic mixture of $\alpha$-hydroxy acid. The carbonyl compound is:

The product $A$ in the above reaction is

Identify $(A)$ in the following reaction sequence:
$\mathop {(A)}\limits_{\text{gives positive iodoform Test}}$ $\xrightarrow[(ii) H^{+}, H_2O, (iii) \text{conc. } H_2SO_4/\Delta ]{(i) CH_3MgBr} (B)$ $\xrightarrow{O_3/Zn, H_2O}$

Which product is obtained by the reduction of propionaldehyde with amalgamated zinc and concentrated $HCl$?

$CH_3-CHO \xrightarrow{dil. OH^{-} / \Delta}$ Major product formed in the above reaction is:

What is the product formed when propanal reacts with dilute sodium hydroxide?