Identification of Oxoacids of Chlorine from Sodium Hydroxide Reaction

To determine the identities of $P$ and $Q$, we analyze the chemical reactions of chlorine gas ($\text{Cl}_2$) with sodium hydroxide ($\text{NaOH}$) under different reaction conditions:

1. Reaction with Cold and Dilute $\text{NaOH}$: When $\text{Cl}_2$ gas reacts with cold and dilute $\text{NaOH}$ solution, disproportionation occurs to form sodium chloride and sodium hypochlorite ($\text{NaClO}$): $\text{Cl}_2 + 2\text{NaOH}_{\text{(cold, dilute)}} \rightarrow \text{NaCl} + \text{NaClO} + \text{H}_2\text{O}$ Here, $\text{NaClO}$ is the sodium salt of hypochlorous acid ($\text{HClO}$). Thus, $P$ is the sodium salt of hypochlorous acid.

2. Reaction with Hot and Concentrated $\text{NaOH}$: When $\text{Cl}_2$ gas reacts with hot and concentrated $\text{NaOH}$ solution, a further disproportionation reaction occurs, producing sodium chloride and sodium chlorate ($\text{NaClO}_3$): $3\text{Cl}_2 + 6\text{NaOH}_{\text{(hot, conc.)}} \rightarrow 5\text{NaCl} + \text{NaClO}_3 + 3\text{H}_2\text{O}$ Here, $\text{NaClO}_3$ is the sodium salt of chloric acid ($\text{HClO}_3$). Thus, $Q$ is the sodium salt of chloric acid.

Therefore, $P$ and $Q$ are the sodium salts of hypochlorous and chloric acids, respectively.

Correct Option: A