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 solve the problem, we need to determine what product is formed when acidified KMnO₄ oxidizes sulphite.

1. Understanding the Reaction:
In an acidic medium, potassium permanganate (KMnO₄) is a strong oxidizing agent. It oxidizes sulphite ions (SO₃^2-) to sulphate ions (SO₄^2-).

2. Oxidation of Sulphite:
The sulphite ion (SO₃^2-) gets oxidized by the KMnO₄ in the presence of an acidic medium. The manganese in KMnO₄ undergoes reduction from +7 oxidation state to +2 oxidation state, forming Mn²⁺.

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

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

Final Answer:
Acidified KMnO₄ oxidizes sulphite (SO₃^2-) to sulphate (SO₄^2-).