Answer
- $N{H_4}^+$ is a weak acid.
Work Step by Step
- $N{H_4}^+$ isn't in the common strong acids list:
$HCl, HI, HBr, HClO_4, HClO_3, HNO_3$ and $H_2SO_4$
- You can also analyze the table $14.2$, and see that, its $K_a$ value is $5.6 \times 10^{-10}$.
Compounds with $K_a < 1$ are considered: Weak acids.