Question

WHY SOAP DOES 'T WORK IN HARD WATER?

Answer 1

Here is your answer:
Soaps are potassium or sodium of long chain carboxylic acids. It can make water hard after reacting with magnesium or calcium salts. So when we use soap and hard water, the amount of lather that is produced is very small. The hard water produces an insoluble precipitate known as skum