Question

What is the total hardness of water in mg/L if the concentration of Ca and Mg are 56.7 mg/L and 9.8 mg/L?

(a) 182.1

(b) 66.5

(c) 133

(d) 91.05

I have been asked this question by my school principal while I was bunking the class.

I would like to ask this question from Concentration-I in division Introductory Concepts of Chemical Process Calculation

Answer 1

Right choice is (a) 182.1

To elaborate: g CaCO3 /g Ca= 2.5 and g CaCO3 /g Mg = 4.118

Hardness of water = 2.5(56.7) + 4.118(9.8).