In determination of hardness by EDTA method, 50ml of standard hard water required 30ml of EDTA solution while 50ml of sample hard water consumed 20ml of EDTA solution. After boiling 50ml of same sample required 10ml of EDTA solution. Calculate the permanent hardness.
The question was asked in final exam.
I would like to ask this question from Problems, Units and Formulae topic in chapter Water of Applied Chemistry