H(2)PO(4)^ - ^ H(2)O ——> H(3)O^ + ^ + HPO(4)^[-2]^ which of the following is a base conjunction acid pair
1. H(2)O and H(3)O^+^
2. H(2)O and H(2)PO(4)^-^
3. H(2) PO(4)^-^ and HPO(4)^[-2]^ 4. H(2)PO(4)^-^ and H(3)O^+^
^ ^- these arrows show what is above the last number