Question

Concentrated hydrochloric acid is 38% HCl by mass, and it has a density of 1.189 g/ml at 20 celsius. The density of water at 20 celsius is 0.9982 g/ml. If all the HCl were somehow removed from 1.000 liters of this solution at 20 celsius, what volume of water would remain? The answer is 739 mL but I don't know how you get that.

Answer 1

volume of solution = 1Litre = 1000 ml

density of solution = 1.189 g/ml

mass of solution = volume of solution × density of solution

= 1000 × 1.189 = 1189 g

a/c to question,

concentration of hydrochloric acid is 38% by weight.

so, mass of hydrochloric acid in 1189g of solution = 38% of 1189 = 451.82g

mass of water in solution = mass of solution - mass of HCl

= 1189g - 451.82g

= 737.18g

now volume of water = mass of water/density of water

= 737.18/0.9982 ml

≈ 739 ml