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 due to the presence of bicarbonates, chlorides and sulphates of `Ca` and `Mg` on it. These `Ca^(2+)` and `Mg^(2+)` ions react with the anions of fatty acids present in soaps to form curdy white precipitates. As a result, hard water does not produce lather with soap immediately.