Question

Acidified KMnO$_4$ oxidizes sulphite to:

• A. SO$_3^{2-}$
• B. SO$_4^{2-}$
• C. SO$_2$(g)
• D. S$_2$O$_8^{2-}$

Hint:

KMnO$_4$ in acidic conditions oxidizes sulphite to sulfate.

Answer 1

The Correct Option is B

To address the problem, we must identify the product resulting from the oxidation of sulphite by acidified KMnO₄.

1. Reaction Analysis:
In acidic conditions, potassium permanganate (KMnO₄) acts as a potent oxidizing agent. It converts sulphite ions (SO₃^2-) into sulphate ions (SO₄^2-).

2. Sulphite Oxidation Process:
The sulphite ion (SO₃^2-) is oxidized by KMnO₄ in an acidic environment. The manganese within KMnO₄ is reduced from a +7 oxidation state to a +2 oxidation state, yielding Mn²⁺.

3. Balanced Chemical Equation:
The balanced redox reaction in an acidic solution is as follows:

2 KMnO₄ + 5 SO₃^2- + 4 H₂O → 2 Mn²⁺ + 5 SO₄^2- + 4 OH^-

Final Determination:
Acidified KMnO₄ converts sulphite (SO₃^2-) to sulphate (SO₄^2-).