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Permanent hardness of water cannot be removed by which one of the following methods?

Options

  1. ATreatment with washing soda
  2. BCalgon's method
  3. CBoiling
  4. DIon exchange method

Correct answer

C. Boiling

Step-by-step solution

The permanent hardness of water is due to presence of chloride and sulphates salts of calcium and magnesium. This type of hardness can be removed by Calgon's method, Ion-exchange method and treatment with washing soda. Boiling can remove only the temporary hardness of water but not the permanent hardness.

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