How much water must be evaporated from 100 gallons of a 10% brine (saltwater) solution to get a 40% brine (saltwater)?

1 Answer
Oct 18, 2015

75 gallons of water

Explanation:

Let

V_1 be volume of 10 % brine solution

V_2 be volume of 40 % of brine solution after evaporation of water

Mass of brine in volume of V_1 = V_1*(10/100) = 0.1V_1

Mass of brine in 100 gallons of 10 % brine solution = 0.1X100 =10 =

Mass of brine in volume of V_2 = V_2*(40/100) = 0.4V_2

Total mass of the salt is constant due to evaporation

0.4V_2 = 10
V_2 = 10/0.4 =25 gallons

Volume of water evaporated = V_1 - V_2

Volume of water evaporated = 100-25 = 75 gallons