## Chemistry (4th Edition)

$(a)$, $(b)$ and $(c)$ are capable of forming buffers.
1. To be capable of forming a buffer, the solution needs: - A weak acid. - Its conjugate base. (a) Weak acid: $HCN$; Conjugate base: $CN^-$; (b) Weak acid: $HS{O_4}^-$; Conjugate base: $S{O_4}^{2-}$ (c) Weak acid: $N{H_4}^+$; Conjugate base: $NH_3$ (d) Weak acid: Missing ($HI$ is a strong acid).