For making our home,s wall its react with cement
It is used:(i) in the preparation of cement, glass and calcium carbide.\xa0(ii) in the purification of sugar(iii) in drying alcohol and non-acidic gases like ammonia etc.,(iv) in softening of hard water.\xa0(v) as a flux in the extraction of metals.\xa0(vi) in agriculture as a fertiliser, disinfectant and germicide.
Cao is used for Making calcium hydroxide and calcium hydroxide is used for (putty) plane the surface of walls
It can be added to rivers after acid rain to control the ph of acid present in water.