Answer
From strongest to weakest:
$NH_3, C_5H_5N, H_2O, N{O_3}^-$
Work Step by Step
1. Analyzing the table 13-3 (Page 551), we get that:
$NH_3$ is a weak base, with $K_b = 1.8 \times 10^{-5}$
$C_5H_5N$ is a weak base, with $K_b = 1.7 \times 10^{-9}$
We know that, the $K_b$ of water is $1 \times 10^{-14}$
And $N{O_3}^-$ is the conjugate bases of a strong acid: $HNO_3$, so it is very weak: $K_b < 10^{-14}$.
2. So, ordering from the higher Kb value, to the lower one, we got:
$NH_3, C_5H_5N, H_2O, N{O_3}^-$
