How can picric acid and benzoic acid be distinguished?

Assertion $(A)$: $pK_a$ of phenol is $4.19$ and that of benzoic acid is $10$.
Reason $(R)$: Phenoxide ion is stabilised by non-equivalent resonance structures,whereas benzoate ion is stabilised by two equivalent resonance structures.
The correct option among the following is:

Give the reactions of phenol with zinc dust and oxidation.

When carbolic acid is heated with concentrated nitric acid in the presence of concentrated sulphuric acid,it forms:

The electrophile involved in the below reaction is:

In the following sequence of the reaction, the final product "$C$" is:
$Phenol \xrightarrow[NaOH]{CHCl_3} A \xrightarrow[H_3O^+]{} B \xrightarrow[Oxidation]{} C$