Question

You wish to create 25 mL of a mixture that is 2.5% HCl. You have one solution that is 4% HCl and another one that is 1% HCl. How much of each solution should you use in the mixture?

a) 15 mL of 4% HCl solution and 10 mL of 1% HCl solution

b) 20 mL of 4% HCl solution and 5 mL of 1% HCl solution

c) 10 mL of 4% HCl solution and 15 mL of 1% HCl solution

d) 25 mL of 4% HCl solution and 0 mL of 1% HCl solution

Answer 1

To create a 2.5% HCl mixture, mix 15 mL of the 4% HCl solution with 10 mL of the 1% HCl solution.

Step-by-step explanation:

To create 25 mL of a 2.5% HCl mixture using a 4% HCl solution and a 1% HCl solution, we can use the method of algebraic equations to find the correct proportions. Let x represent the volume of the 4% solution and (25 - x) represent the volume of the 1% solution. Set up the equation based on the concentration of HCl in each solution multiplied by its volume and the desired final concentration:

0.04x + 0.01(25 - x) = 0.025(25)

Solving for x, we get x = 15 mL and 25 - x = 10 mL. Therefore, we will need 15 mL of the 4% HCl solution and 10 mL of the 1% HCl solution to obtain the desired concentration.

The correct answer is (a) 15 mL of 4% HCl solution and 10 mL of 1% HCl solution.