## Chemistry: The Central Science (13th Edition)

$NH_3$ is a weak base. Conjugate acid: ${NH_4}^+$, which is a weak acid.
$NH_3(aq) + H_2O(l) --> {NH_4}^+(aq) + OH^-(aq)$ As we can observe, ${NH_4}^+$ is the conjugate acid of $NH_3$. Since $NH3$ is a weak base, his conjugate acid will be weak.