What is the [OH-] in a solution that has a [H3O+] = 2.0 x 10-2 M?

Jun 22, 2018

$5.0$ x ${10}^{-} 13$

Explanation:

We'll use the ionic product of water formula,

${K}_{w}$ = $\left[{H}_{3} {O}^{+}\right] \cdot \left[O {H}^{-}\right] = 1.0$ x ${10}^{-} 14$

rearrange the equation,
$\left[O {H}^{-}\right]$
$= 1.0$ x ${10}^{-} 14$ / $\left[{H}_{3} {O}^{+}\right]$
$= 1.0$ x ${10}^{-} 14$ / $2.0$ x ${10}^{-} 2$
$= 5.0$ x ${10}^{-} 13$