Question

What is the concentration, in ppm, if 0.025 g of KCl is dissolved in 100 grams of water?

(a) 4 x 10^3 ppm

(b) 250 ppm

(c) 2.5 x 10^-4 ppm

(d) 2.5 ppm

This question was addressed to me during an online exam.

This is a very interesting question from Expressing Concentration of Solutions topic in section Solutions of Chemistry – Class 12

Answer 1

The correct answer is (b) 250 ppm

The explanation is: ppm = (mass of solute/mass of solution) x 10^6

Mass of solute = 0.025 g

Mass of solution = 0.025 + 100 = 100.025 g

Concentration in ppm = (0.025/100.025) x 10^6 = 250 ppm.