Permanent hardness of water may be removed by the addition of___________?
Correct answer: A. Sodium Carbonate
- A. Sodium Carbonate
- B. Alum
- C. Potassium Permanganate
- D. Lime
Explanation
Sodium carbonate reacts with dissolved calcium and magnesium salts and precipitates them, removing permanent hardness. Alum is mainly used as a coagulant, while lime is chiefly used for temporary hardness.
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