Ten liters of distilled water was mixed with 20 liters of a15% acid solution. what is the concentration of acid in the new solution?

By adding distilled water to a 15% acid solution, the acid becomes more diluted and percentage of acid is lowered.

we can use the following formula

c1v1 = c2v2

where c1 is concentration in percentage form and v1 is volume of the concentrated solution

c2 is concentration and v2 is volume of the diluted solution

substituting these values in the formula

15% x 20 L = C x 30 L

C = 10%

concentration of acid in new solution is 10%