MCQ Detailed View

Potassium Permanganate (KMnO₄) is a dark purple inorganic compound commonly used in water treatment. Its primary function in purifying drinking water is based on its strong oxidising properties. As an oxidising agent, KMnO₄ can react with a wide variety of organic and inorganic substances in water, breaking them down into harmless compounds.

In water purification, KMnO₄ is effective in removing iron (Fe²⁺), manganese (Mn²⁺), and hydrogen sulfide (H₂S). These substances can cause bad taste, odor, and staining in water. When KMnO₄ oxidises Fe²⁺ and Mn²⁺ ions, it converts them into insoluble forms, which can then be removed by filtration. This process improves water clarity and quality.

KMnO₄ also acts as a mild disinfectant. By oxidising organic matter, it reduces the number of microorganisms, including bacteria, present in water. Unlike reducing agents, which donate electrons, KMnO₄ accepts electrons during oxidation, making it highly effective in eliminating contaminants.

Its use in water treatment is advantageous because it is stable, easy to handle, and leaves only a slight pink color that fades with time. KMnO₄ is not used to dissolve impurities directly or act as a reducing agent. Its sterilising action is secondary and occurs due to its oxidising ability, not through direct chemical sterilisation.

Understanding the oxidising nature of KMnO₄ and its application in water purification is a key concept in inorganic chemistry. It illustrates how inorganic compounds are used in daily life to improve water quality and maintain public health.