Answer
(a) $H_2S$
(b) $H_2CO_3$
(c) $HCO_3^-$
(d) $H_3PO_4$
(e) $H_2PO_4^-$
(f) $HPO_4^{2-}$
(g) $H_2SO_4$
(h) $HSO_4^-$
(i) $HSO_3^-$
Work Step by Step
Since the conjugate acid of a base is formed by the base + 1 ($H^+$), all we need to do is:
1. Add a Hydrogen to the compound.
2. Sum 1 to the charge.