Question

To prepare m 50 100 ml oxalic acid solution and using this solution to determine the strength of kmno4 solution in gm/lt

Answer 1

Potassium permanganate is a strong oxidising agent and in the presence of sulfuric acid it acts as a powerful oxidising agent. In acidic medium the oxidising ability of KMnO4 is represented by the following equation.

In acidic solution,

MnO4– + 8H+ + 5e– → Mn2+ + 4H2O

Solution containing MnO4– ions are purple in colour and the solution containing Mn2+ ions are colourless and hence permanganate solution is decolourised when added to a solution of a reducing agent. The moment there is an excess of potassium permanganate present the solution becomes purple. Thus KMnO4 serves as self indicator in acidic solution.