1. 15 ppm means 15 parts in million (106 ) parts by mass in the solution
% of mass = \(\frac{15}{10^6}\) x 100 = 1.5 x 10-4
2. Taking 15g chloroform in 106 g of the solution
Mass of the solvent = 106 g
Molar mass of CHCl3 = 12 + 1 + (3 x 35.5) = 119.5 g mol-1