Question

How much of a 7% HCL acid solution needs to be mixed with how much of a 15% HCL acid solution so that you obtain 20 ml of a 12% HCL acid solution? (show details please!)

Answer 1

7.5 mL of 7% HCl acid solution and 12.5 mL of 15% HCl acid solution

Explanation:

If x is the volume of 7% HCl acid solution, and y is the volume of 15% HCl acid solution, then:

x + y = 20

0.07 x + 0.15 y = 0.12 (20)

Solve the system of equations using elimination or substitution. Using substitution:

0.07 x + 0.15 (20 − x) = 0.12 (20)

0.07 x + 3 − 0.15 x = 2.4

0.6 = 0.08 x

x = 7.5

y = 12.5

You need 7.5 mL of 7% HCl acid solution and 12.5 mL of 15% HCl acid solution.