CHEMISTRY COMMUNITY

A careless laboratory technician wants to prepare 200.0 mL of a 0.025 HCl (aq) solution but uses a volumetric flask of volume 250.0 mL by mistake. (a) what would the pH of the desired solution have been? (b) What will be the actual pH of the solution as prepared?

HCl is a strong acid so the key is the find the concentration of H3O+. You can find the moles first and divide by the real volume of the container.