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 #"H"_3"O"^(+)#. If you add #10^(-6) "M"# 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 #["H"_3"O"^(+)]# due to adding such an acid to water. The #"HCl"# then suppresses the #"H"_3"O"^(+)# in water.