Chemistry Dilution

Question

What volume of water must be added to 8 mL of concentrated 17.4 M HCl solution to dilute it to 7 mol/L?

Answer 1

For this type of problem, we can use the equation C₁V₁ = C₂V₂, where C is concentration and V is volume. Since we first need to solve for the final volume of the solution, we can rearrange the equation to look like this:

V₂ = C₁V₁/C₂ = (17.4 M)(0.008 L)/7M = 0.0199 L, or 19.9 mL

Since we started with 8 mL of the concentrated solution, we just subtract that from the value above to solve for how much water to add.

19.9 mL - 8 mL = 11.9 mL

Hope this helps!