Question

why do soaps form scum with hard water

Answer 1

When a soap is used in hard water, a solid substance we call scum forms. Thisis because charged calcium and magnesium particles (called ions ) present in the water react with soap toform an insoluble substance.

I hope this is the correct answer for you.

Answer 2

Explanation:

hard water contains calcium and magnesium and soap is basically sodium or potassium salt of higher fatty acids when soap is added to hard water corresponding calcium and magnesium salts are formed which being in soluble that dissipated this precipitated second is come reaction taking place