Statement 1 : Acids that have more than one proton that can be donated to base are called polyprotic acids.Statement 2 : For all diprotic acids, the equilibrium constant Ka2, for the second stage of ionisation is smaller than the equilibrium constant, Ka1, for the first stage of ionisation.

A polyprotic acid is a compound which may lose more than 1 proton.  The constant for dissociation of the first proton may be denoted as Ka1 and the constants for dissociation of successive protons as Ka2, etc. Phosphoric acid, H3PO4, is an example of a polyprotic acid as it can lose three protons.In polyprotic acids, Ka1>Ka2>Ka3>...