Question

5 litres of a solution contains 25 mg of $CaC{O}_3$.What is its concentration in ppm ? (mol. wt. of $CaC{O}_{3}is100)$

• A. 25
• B. 1
• C. 5
• D. 250

Answer 1

Answer: (C)

5L dilute solution = 5 kg = 5000 g
Mass of solute = 25 mg = $25\times 10^{-3}$ g
' ppm of $CaC{O}_3$ in solution
= $\frac{25}{10^{-3}g}5000g\times 10^6$ = 5 ppm.