Benzaldehyde reacts with ammonia to form

In a set of the given reactions,acetic acid yielded a product $C$. Product $C$ would be:
$CH_3COOH + PCl_5 \to A$ $\xrightarrow{C_6H_6, \text{anh. } AlCl_3} B$ $\xrightarrow{C_2H_5MgBr, \text{ether}} C$

When liquid $A$ is treated with a freshly prepared ammoniacal silver nitrate solution,it gives a bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid $B$ also forms a white crystalline solid with sodium hydrogensulphite but it does not give a test with ammoniacal silver nitrate. Which of the two liquids is an aldehyde? Write the chemical equations of these reactions also.

Which reagent is suitable for the following transformation?

Ethylene is converted to $X$ on passing through a mixture of an acidified aqueous solution of palladium chloride and cupric chloride. Which of the following reagents readily take part in addition reaction with $X$?

The following reagent converts $C_6H_5COCHO$ to $C_6H_5CHOHCOONa$.