Aldehydes Ketones And Carboxylic Acids

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