Question

Why are soaps not considered suitable for washing clothes in a region where water is hard? How is this problem overcome?

Answer 1

Soaps are not suitable for washing clothes in hard water because they react with calcium and magnesium ions present in hard water to form insoluble scum, reducing their cleansing ability. This problem is overcome by using detergents, which do not form scum in hard water and clean effectively.

Answer 2

Because the calcium, magnesium ions in hard water react with the soap molecules to form insoluble precipitates called “scum,” which adhere to clothing and hinder the soap's ability to clean, soaps are not recommended for use in hard water. This problem is resolved by using synthetic detergents, which are more effective in hard water conditions because they do not form precipitates with hard water ions.