Question

In general, for a diprotic acid, ka2 << ka1. this is reasonable because

Answer 1

Consider a diprotic acid H2A

After one H+ is removed, 2nd H+ should be removed from HA-

Due to negative charge, the compound will be less likely to loose H+ as compared to H2A

So, there will be less dissociation of HA- as compared to H2A

So, it can be assumed that Ka2 << Ka1