Question

The pH of a solution containing $N{H}_{4}OH$ and $N{H}_4^{+}$ is 9. If $\left[N{H}_4^{+}\right]$ = 0.1 M and Ka of $N{H}_4^{+}$ is $5\times {10}^{-10}$ then what is $\left[N{H}_{4}OH\right]$ ?

Answer 1

$K_a=\frac{\left[N{H}_4^{+}\right]\left[O{H}^{-}\right]}{\left[N{H}_{4}OH\right]}$

$\left[N{H}_{4}OH\right]=0.1$ $M$

$K_a$ of $N{H}_4^{+}=5\times {10}^{-10}$

pH of a solution containing $N{H}_{4}OH$ and $N{H}_4^{+}$ is $9$

$\frac{0.1\times 2\times {10}^{-5}}{\left[N{H}_{4}OH\right]}=5\times {10}^{-10}$

$⟹\left[N{H}_{4}OH\right]=2.4088\times {10}^{31}$