Assuming that the volumes are additive, what volume of water must be added to 35.0mL of 23.0 M HCl to make a solution which is 3.00 M?

Answer 1

mL x M = mL x M
35.0 mL x 23.0M = mL x 3.00M
Solve for mL which will be the TOTAL volume. The volume to be added will be 35.0 mL less than that.

Answer 2

233.3ml