50 ml of std water containing 1 mg of pure CaCO3 per ml consumed 20 ml of EDTA 50 ml of water sample consumed 25 ml of EDTA using EBT as indicator . Calculate hardness of water.

1ml of std water = 1mg of KOH

50 ml of std water = 50 mg of CaCO3

50 ml of std water = 20 ml of EDTA

1 mi of EDTA = 50 /20mg of CaCO3

= 2.5 mg of CaCO3

1000 ml of H2O = 1000/50 X 25 X 2.5

Total hardness of WATER = 1250 ppm