Question

A sample of hard water is found to contain 40 mg of ca+2 ion per litre. The amount of washing soda (na2co3) required to soften five litres of the sample would be -

Answer 1

Explanation:

Amount of CaCO3 present per litre of water = 1.95mg. ∴ wt of 1 ... (b) Eqwt of Ca++ = Mol.wt/Charge = 40/2 = 20 ... Na2CO3 is required to soften 1 litre of hard water.