Answer
(a) ${IO_3}^-$
(b) $C_6H_5COO^-$
(c) ${PO_4}^{3-}$
(d) $C_2H_5NH_2$
Work Step by Step
To find the conjugate base of an acid, all you need to do is remove one H atom from the formula, and subtract 1 from the charge. (Because you removed one $H^+$)
Conjugate bases are the result from removing a proton from an acid.
