Question

An acid which can decolourise purple coloured potassium permanganate solution is ______.

Options

• sulphuric acid

• citric acid

• carbonic acid

• hydrochloric acid

Answer 1

An acid which can decolourise purple coloured potassium permanganate solution is citric acid.

Explanation:

Potassium permanganate (KMnO₄) is a very powerful oxidising agent with a distinct deep purple colour. When citric acid (a reducing agent) is added to it, a redox reaction occurs where the purple permanganate ions \[\ce{(MnO^-_4)}\] are reduced to manganese ions (Mn²⁺). Because manganese (Mn²⁺) ions are completely colourless in solution, the entire mixture loses its purple tint and becomes clear.