CBSE Class 12-science Answered

Hard Water

Soft Water

It is an impure form of water having a high mineral contents, like Ca, Mg, sulphides, chlorides, bicarbonates etc.

It is little alkaline and the pH is greater than 7.8 as 8 or more.

It does not give lather with soap and can harm the boiler, cooling towers, and also injurious to health if some other elements like Arsenic is present.

The hardness is above 120 gm/L

Well water, Pond Water etc is Hard Water

It is a pure form of water in which the only ion like Sodium ionand chloride ions is present.

It's pH ranges from 5.5 to 7.7.

It gives lather with soaps and do not harm by any means, whereas it is used in chemical processes and for drinking and all life processes.

Its hardness is between 0-60 gm/L

Rain Water is sof water