Question

washing with soap is difficult in hard water

Answer 1

it is because it does not form lather in hard water due to presence of calcium or magnesium ions present in hard water

Answer 2

Here is your answer.....

Yes, washing with soap in hard water is difficult because hard water contains calcium and magnesium salts so firstly the soap reacts with the salts and form an insoluble precipitate called scu* which interfers in washing.

Hope it helped you
(^_^)