Concept:Potassium Permanganate (\( KMnO_4 \)) is a famous, incredibly strong oxidizing agent, especially in acidic environments. Sulfur dioxide (\( SO_2 \)) often acts as a reducing agent.
Formula:$$2KMnO_4 + 5SO_2 + 2H_2O \rightarrow K_2SO_4 + 2MnSO_4 + 2H_2SO_4$$
Solution:- In \( KMnO_4 \), Manganese is in a highly unstable \( +7 \) oxidation state and desperately wants to acquire electrons.
- In \( SO_2 \), Sulfur is in a \( +4 \) state, but can easily be oxidized to the \( +6 \) state (sulfate).
- \( SO_2 \) provides the electrons to \( KMnO_4 \), causing Manganese to be reduced from \( +7 \) to \( +2 \) (evidenced by the deep purple solution turning colorless).
- Because \( SO_2 \) forces \( KMnO_4 \) to gain electrons, \( SO_2 \) acts as the reducing agent.
Why other options are incorrect:\( SO_2 \) does not oxidize \( KMnO_4 \); it does the exact opposite. \( KMnO_4 \) is highly active in acidic media, not inert.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.