The given reaction is: $R_2C=O + HCN \rightarrow R_2C(OH)CN$

The structure of product $C$,formed by the following sequence of reactions is :
$CH_3COOH + SOCl_2$ $\longrightarrow A$ $\xrightarrow[AlCl_3]{Benzene} B$ $\xrightarrow[H^{+}]{KCN} C$

The reactant $(A)$ will be:

In the given set of reactions,identify $D$:
$CH_3COOH$ $\xrightarrow{SOCl_2} A$ $\xrightarrow[Anhy. AlCl_3]{Benzene} B$ $\xrightarrow{HCN} C$ $\xrightarrow{H_2O} D$

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 $X$?

Arrange the following in the correct order of the rate of Nucleophilic Addition Reaction $(NAR)$:
$(I) \ HCHO$
$(II) \ CH_3CHO$
$(III) \ p-NO_2-C_6H_4CHO$
$(IV) \ p-CH_3-C_6H_4CHO$