Question

Soap forms a precipitate in hard water. Give reason.

Answer 1

Soap does not work properly in hard water. This is primarily because hard water contains salts of calcium and magnesium. When soap is added to hard water, it reacts with these salts to form an insoluble precipitate called scum. This scum sticks to the cloth and decreases the cleansing ability of the soap. In addition, soaps do not give lather with hard water.