Hello, my book says that all acids above H3O+ completely ionize with water so we use "--->" .
The acids under H3O+ and above H2O are in equilibrium with water so we use " <--->".
The acids under H2O are so weak they dont even react with water so we dont use anything.
Now there are some exceptions! For example Na+, LI+, Ba2+, Ca2+, .... are above H2O but they dont use <---> for whatever reason.
My book says that the metal ions of the IA & IIA groups are exceptions, so even though they are above H2O they still arent in equilibrium with water "<--->". They simply dont react with water.
Now my question is for SO42-, this is a base, but it follows the same analogy as acids do. SO42- is under H2O & above OH-, so it should be in equilibrium with water right? So we officialy denote that with "<---->" right?
Thanks in advance!!