Which of the following reagents is used in the conversion of phenol into picric acid?

The major product formed in the following reaction is:

Write the chemical equations for the following reactions:
$(i)$ Reimer-Tiemann reaction
$(ii)$ Kolbe's reaction

In the reaction
Phenol $\xrightarrow{NaOH} (A)$ $\xrightarrow[140^{\circ}C]{CO_2, HCl} (B)$
here $B$ is

The reaction sequence is as follows: $C_6H_5SO_3H$ $\xrightarrow[(ii) H^+]{(i) NaOH} P$ $\xrightarrow{Na_2Cr_2O_7, H_2SO_4} Q$. The ratio of $\sigma$ bonds to $\pi$ bonds in $Q$ is:

Identify the major product formed from the following reaction sequence: