Compound $\mathbf{P}$ is obtained by the hydrogenation of benzoyl chloride with Pd on $\mathrm{BaSO}_4$

On treating compound $\mathbf{P}$ with saturated $\mathrm{NaHCO}_3$ solution, brisk effervescence is observed

Compound $\mathbf{P}$ can be prepared by treating benzene with anhydrous $\mathrm{AlCl}_3$ and $\mathrm{CH}_3 \mathrm{COCl}$

On treating with bromine water, compound $\mathbf{P}$ gives a white precipitate

Both $\mathbf{P}$ and $\mathbf{Q}$ are carbonyl compounds

If $\mathbf{P}$ is the sodium salt of a carboxylic acid, $\mathbf{Q}$ is a primary alcohol

$\mathbf{P}$ and $\mathbf{Q}$ are aromatic compounds

If $\mathbf{P}$ gives a carboxylic acid on acidification, $\mathbf{Q}$ gives a poisonous gas on exposure to air and light