Question

The total hardness value obtained from the complete analysis of a water sample was found to be 120 mg/l. If the value of carbonate hardness is 50mg/l, the non-carbonate hardness and alkalinity are, respectively

• A. 170 mg/l and 50 mg/l
• B. 50 mg/l and 70 mg/l
• C. 170 mg/l and 70 mg/l
• D. 70 mg/l and 50 mg/l

Answer 1

The correct option is D 70 mg/l and 50 mg/l

(c) Carbonate hardness

$=Minimumof\{\begin{array}{c}Totalhardness\\ Alkalinity\end{array}$

Carbonate hardness is 50 mg/l and total hardness is 120 mg/l

$\therefore$ Alkalinity is 50 mg/l

and, Non-carbonate hardness

= Total hardness - carbonate hardness

= (120 - 50) mg/l = 70 mg/l