Question

j) 50 ml std. hard water containing 1.2 gm CaCO3 per lit. required 15 ml EDTA solution for the end point.

Whereas 50 ml sample water required 19 ml of EDTA soln. and 50 ml boiled sample water required

11ml of EDTA soln. for the end point. Calculate, total, temporary and permanent hardness of sample

water in ​

Answer 1

Answer:

Explanation:

1ml of std water = 1mg of KOH 20 ml of std water = 20 mg of CaCO3 25 ml of std water = 20 mg of CaCO3

1 mi of EDTA = 20 /25 mg of CaCO3

= 0.8 mg of CaCO3

1000 ml of H2O = 1000/100 X 18X 0.8

Total hardness = 144 ppm

1000 ml of H2O = 1000/100 X 12X 0.8

Permanent hardness = 96 ppm

Temporary harness = Total hardness – permanent hardness

Temporary harness = 144 – 96

Temporary harness = 48 ppm