Chlorine Reaction with Cold Dilute Alkali

Steps:

• Note conditions: cold aqueous KOH implies dilute solution and low temperature.
• Recall reaction: Cl₂ reacts with cold dilute KOH to form hypochlorite.
• Write equation: Cl₂ + 2KOH → KCl + KClO + H₂O.
• Identify anions: Cl⁻ from KCl and ClO⁻ from KClO.

Why A is correct:

• The equation Cl₂ + 2KOH → KCl + KClO + H₂O directly yields Cl⁻ and ClO⁻ ions in cold conditions.

Why the others are wrong:

• B: IO⁻ involves iodine, unrelated to chlorine reaction.
• C: ClO₂⁻ (chlorite) forms under hot or specific oxidizing conditions, not cold KOH.
• D: ClO₃⁻ (chlorate) requires hot concentrated KOH, not cold dilute.

Final answer: A