Hardness of water is due to presence of salts of

Options

A. `Na^(+)" and "K^(+)`
B. `Ca^(2+)" and "Mg^(2+)`
C. `Ca^(2+)" and "K^(+)`
D. `Ca^(2+)" and "Na^(+)`

Answer

B

Explanation

Hardness of water is due to the presence of bicarbonates, chlorides and sulphates of calcium and magnesium in it. These `Ca^(2+)" and "Mg^(2+)` ions react with the anions of fatty acids present in soaps to form curdy white precipitate. As a result, hard water does not produce foam with soap.