# How do you determine the OH (aq) concentration in 1.0 M aniline (C_6H_5NH_2) solution. (The K_b for aniline is 4.0 x 10^-10?

Jan 8, 2017

You can do it like this:

#### Explanation:

For a weak base:

$\textsf{p O H = \frac{1}{2} \left[p {K}_{b} - \log b\right]}$

Where b is the concentration of the base.

$\textsf{p {K}_{b} = - \log {K}_{b} = - \log \left(4 \times {10}^{- 10}\right) = 9.34}$

$\therefore$sf(pOH=1/2[9.34-log(1)]

$\therefore$$\textsf{p O H = 4.67}$

$\therefore$$\textsf{- \log \left[O {H}^{-}\right] = 4.67}$

$\therefore$$\textsf{\left[O {H}^{-}\right] = 2.14 \times {10}^{- 5} \textcolor{w h i t e}{x} \text{mol/l}}$