Question

Identify 'X' along with the oxidation state of the halogen in the given reaction:
\[ 3\text{Cl}_2 + 6\text{NaOH} \rightarrow 5\text{NaCl} + X + 3\text{H}_2\text{O} \quad \text{(hot and conc.)} \]

• A. NaClO$_2$, +3
• B. NaClO$_3$, +5
• C. NaClO$_2$, +7
• D. NaClO$_3$, +1

Hint:

When chlorine reacts with sodium hydroxide under hot and concentrated conditions, it forms sodium chlorate (NaClO$_3$), where chlorine has an oxidation state of +5. This is a key reaction in the industrial preparation of sodium chlorate.

Answer 1

The Correct Option is B

In this reaction, chlorine (Cl$_2$) reacts with sodium hydroxide (NaOH) in the presence of heat and concentration. The products are sodium chloride (NaCl), water (H$_2$O), and sodium chlorate (NaClO$_3$), where chlorine undergoes oxidation to a +5 oxidation state. The balanced chemical equation for the reaction is: \[ 3\text{Cl}_2 + 6\text{NaOH} \xrightarrow{\text{heat, conc.}} 5\text{NaCl} + \text{NaClO}_3 + 3\text{H}_2\text{O} \] This shows that chlorine in NaClO$_3$ has an oxidation state of +5.
Thus, the correct compound 'X' is NaClO$_3$, and the oxidation state of chlorine is +5.