Which reagent on reacting with phenol gives Salicylaldehyde?

What is the product "C" after following reactions -


 

The functional group which is formed when Phenol is made to react with Chloroform in the presence of dilute Sodium hydroxide

In the following reaction, the product(s) formed is/are:

The major product(s) of the following reaction is/are:

The major product of the following reaction is:

Match the following $\mathrm{pKa}$ values.

$\mathrm{Chlorobenzene}\stackrel{\mathrm{Reaction}-\left(\mathrm{X}\right)}{\to }\mathrm{Phenol}\stackrel{\mathrm{Reaction}-\left(\mathrm{Y}\right)}{\to }\mathrm{Salicylaldehyde}$.

The reactions(s) ${}^{\text{'}}\mathrm{X}^{\text{'}}$ and${}^{\text{'}}\mathrm{Y}^{\text{'}}$ respectively are