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Question
An acid which can decolourise purple coloured potassium permanganate solution is ______.
Options
sulphuric acid
citric acid
carbonic acid
hydrochloric acid
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Solution
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.
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