Question

why do soaps not form leather in hard water ?

Answer 1

Hard water reduces the effectiveness of cleaning agents. Soapis less effective in hard water since it reacts to form a calcium or magnesium salt of the organic acid in the soap and forms a grayish soapscum with no lather. Detergents, on the other hand, lather in both hard and softwater.

Answer 2

because It react with hard water and form a magnesium and calcium ions