Question

" Which salt from the laboratory can be added to tap water to make it hard ? In the experiment how is cleaning capacity of soap compared .

please get me the answer fast
..................its bit urgent. :(

Answer 1

Salt: Sulphate, Chloride or hydrogen Carbonate of Calcium or Magnesium (any one)

By adding equal amount of soap to water taken in two test tubes, shaking vigorously and comparing the length of lather or foam formed in each test tube.

Answer 2

salts of magnesium and calcium increases the hardness of water so sulphates, bicarbonates and nitrates of calcium and magnesium could be added to increase hardness