Metaformaldehyde is:

What is used in the silvering of mirrors?

An organic compound $A$ is oxidized using acidified $K_2Cr_2O_7$ solution to form compound $B$. Compound $B$ gives the $DNP$ test but not the silver mirror test. Then,compound $A$ is:

Which one of the following reactions is a method for the conversion of a ketone into a hydrocarbon?

In the reaction sequence: $CH_3-CHO$ $\xrightarrow{HCN, OH^{-}} (A)$ $\xrightarrow{H_2O/H^{+}, \Delta} \text{Product}$. The product will be:

Isobutyraldehyde on reaction with formaldehyde and $K_{2}CO_{3}$ gives compound '$A$.' Compound '$A$' reacts with $KCN$ and yields compound '$B$,' which on hydrolysis gives a stable compound '$C$.' The compound '$C$' is .... .