Question

In a locality, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory: 1. Sodium sulphate 2. Calcium sulphate 3. Magnesium chloride 4. Sodium chloride 5. Calcium chloride 6. Potassium sulphate Which of the above salts may be dissolved in water to obtain hard water for the experiment? (A) 2, 3 and 5 (B) 1, 2 and 5 (C) 1, 2, 4 and 6 (D) 3 and 5 only

Answer 1

a is the answer because hard water is of calcium and magnesium salt of carboxylic acid

Answer 2

option A is correct
the salts of calcium and magnesium make water hard

hope this helps you