Soft water is the water which can produce lather with soap easily.
Hard water is the water which cannot produce lather with soap easily.

The hardness of water is caused due to the presence of soluble salts of magnesium and calcium.

The salts which bring hardness in water are calcium bicarbonate (Ca(HCO3)2), calcium sulphate (CaSO4), magnesium bicarbonate (Mg(HCO3)2), magnesium chloride (MgCl2), etc.

Any two advantages of hard water are:

(i) It contains calcium salt dissolved in it which helps to strengthen the bones and teeth.

(ii) It is used in beer industries.

Any two disadvantages of hard water are:

(i) It leads to the consumption of more soap while washing clothes.

(ii) A bright white cloth becomes dull due to the salts dissolved in water.