Compound $\mathrm{P}\left(\mathrm{C}_8 \mathrm{H}_8 \mathrm{O}\right)$ gives a red orange precipitate with 2,4-DNP reagent and it does not reduce Fehling's reagent. On drastic oxidation with chromic acid, $P$ gives an aromatic product $Q$ that produces effervescence on treating with aq. $\mathrm{NaHCO}_3$. Compounds P and Q , respectively, are :

$$ \text { Match List I with List II: } $$

Choose the correct answer from the options given below :

In a test tube containing a salt, a few drops of dilute $\mathrm{H}_2 \mathrm{SO}_4$ was added, which gave colourless vapours having the smell of vinegar. The vapours turned the blue litmus paper red.

Identify the correct anion from the following :

Identify the suitable reagent for the following conversion.