Question

The hardness of 1000 litres of a water sample was removed by passing it through a zeolite softener which required 30litres of NaCl solution containing 1.5 gm/L NaCl for regeneration. The hardness of the water sample will be ___________

(a) 54.2 ppm

(b) 12.9 ppm

(c) 45 ppm

(d) 38.46 ppm

I have been asked this question in an international level competition.

My doubt is from Zeolites in chapter Water and its Treatment of Engineering Chemistry II

Answer 1

Right option is (d) 38.46 ppm

Easiest explanation: The hardness of the water sample will be 38.46 ppm.