Eduprobe
Question:
Hard water required for an experiment is not available in a school laboratory. However, the following salts are available in the laboratory. Select the salts which may be dissolved in water to make it hard for the experiment: (1) calcium sulphate (2) sodium sulphate (3) calcium chloride (4) potassium sulphate (5) sodium hydrogen carbonate (6) magnesium chloride
1, 2 and 4
1, 3 and 6
3, 5 and 6
2, 4 and 5
Solution:
Hard water is the water that contains salts of calcium and magnesium principally as bicarbonates, chlorides, and sulfates. Hence, salts like calcium sulphate (1), calcium chloride (3) and magnesium chloride (6) can be added to make hard water.