Originally Posted by SpanishCastleAle
So pH is a measurement of H+ ions. Suppose we have a substance accepts or donates OH- ions (implying it does not directly affect the H+ ions)...how does that change the pH? Since pH is a measure of the H+ and not the OH-.
darven_stout aleady answered this, but since this may be necessary for better understanding how the addition of OH- and other bases lower the pH I should add this as well.
Once you look deeper into that subect you will see that all this pH stuff is held together by a number of equilibrium equations that all need to be satisfied. While this is very fascinating I made an effort to stay away from it as not to scare readers away. But that particular principle needs to be mentioned.