How many ml of a 15% acid solution and how many ml of a 3% acid solution must be mixed to get 45 ml of a 7% acid solution?

15 mL of 15% acid solution and 30 mL of 3% acid solution

Explanation:

The total number of moles of the mixture is equivalent to the addition of the number of moles of the first solution and the number of moles of the second solution . Mathematically,

The volume of the mixture = 45 mL

The volume of first solution = x

The volume of second solution = 45 - x

Therefore:

0.15x + 0.03(45-x) = 0.07*45

0.15x + 1.35-0.03x = 3.15

0.12x = 1.8

x = 15

Thus, the volume of the first solution is 15 mL while the volume of the second solution is 30 mL.

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