Question

What is the concentration of a new solution obtained by mixing 25ml of water with 125ml of a 20% salt solution in water?

Answer 1

Given that the concentration of salt in a 125 ml of salt solution is 20%, this means that the ratio of salt to water in the solution is 20 : 80 = 1 : 4.

Thus, the amount of salt in the 125 ml 20% salt solution is given by 20% of 125 = 0.2 x 125 = 25ml and the amount of water in the 125ml 20% salt solution is 125 - 25 = 100 ml.

When 25 ml of water is added to the 125 ml 20% salt solution, the new amount of water is 100 + 25 =125 and the amount of salt remain 25 ml.

Thus, the new volume of the solution is 125 + 25 = 150 ml and the proprtion of salt in the new solution is given by 25 / 150 = 0.1667

Therefore, the concentration of a new solution obtained by mixing 25ml of water with 125ml of a 20% salt solution in water is 16.67%