Answer
See the answer below.
Work Step by Step
a) Acid/Conj. base: $CH_3CO_2H/CH_3CO_2^-$, base/conj. acid: $C_5H_5N/C_5H_5NH^+$
b) Acid/Conj. base: $HSO_4^-/SO_4^{2-}$, base/conj. acid: $N_2H_4/N_2H_5^+$
c) Acid/Conj. base: $[Al(H_2O)_6]^{3+}/[Al(H_2O)_5OH]^{2+}$, base/conj. acid: $OH^-/H_2O$