Why doesn't the concentration of H3O+ decrease when you add HCl to water?

Shouldn't it according to the common ion effect or Le Chatelier's Principle?

1 Answer
Mar 2, 2018

Because you added a strong acid?


The HCl is going to dissociate to pretty much completion and give you lots of H3O+. If you add 106M of HCl, let's say... then sure, it would be suppressed. But who adds that?

Ordinary HCl solutions are around 1 M, so we'll never see the effects of Le Chatelier's principle affect [H3O+] due to adding such an acid to water. The HCl then suppresses the H3O+ in water.