The hardness OF 100.000 lit of water was completely removed by passing it through a zeolite softener. The softener then required 40o lit of NaCl containing 100 gm /lit NaCl for regeneration Calculate hardness of water

Total amount of NaCl required for regeneration = 100 x 103 x 400 = 4 x 107 58.5 gm of NaCl = 50 gm of CaCO3

4 x 107 mg NaCl = 4 x 107/58.5 X 50

CaCO3 equivalent of NaCl =3.419 X 107mg of CaCO3

Volume of water = 100,000 lit

Hardness of water =CaCO3 equivalent of NaCl /hardness

Hardness of water =3.419 X 107 /100,000

Hardness of water =3.419 X 102ppm