Problem when over adjusting pH - (Aug/18/2005 )

Let say I want to make a solution of pH 8.0. But if I accidentally adjust it to 8.5 (by adding NaOH), why can't I add HCl to readjust it to 8.0?

Thank you very much for your help.

because this affects the salt concentration in your solution (Na from the NaOH and Cl from the HCL associate) Of course you CAN but you don't want to do this if the salt concentration is important to your procedure (probably is in most situations...) I also think this depends somewhat on how much you add to what volume of solution, for example, adding one drop of HCL will not significantly affect the salt concentration of a 1L solution....