## Chemistry: Atoms First (2nd Edition)

$HClO_4$, $HClO_2$, $N{H_4}^+$ and $H_2O$
Using table 13-2, from page 531, and knowing that: Strong acids: $K_a > 1$ Water: $K_a = 1.0 \times 10^{-14}$ Identify each acid ka value: $HClO_2$: $K_a = 1.2 \times 10^{-2}$ $H_2O$: $K_a = 1.0 \times 10^{-14}$ $N{H_4}^+$: $K_a = 5.6 \times 10^{-10}$ $HClO_4$: $K_a > 1$ - Ordering in decreasing order, we obtain: $HClO_4, HClO_2, N{H_4}^+, H_2O$ - Remember that a greater $K_a$ value means a stronger acid.