A student dilutes a solution so that its pH changes from 2.4 to 4.4.
10mL of the original solution was diluted by how many mL?
pH = -log(H^+).
pH 2.4; (H^+) = 3.98E-3
pH 4.4 = 3.98E-5
So it has been diluted by 100 times.
3.98E-3 x (10 mL/x mL) = 3.98E-5
Solve for X. You should have gone to 1000 mL. By the way, you should use the same screen name. We can help you better if you do.