Answer
$8.3\times10^{-7}$, Basic
Work Step by Step
For this we need to use the equations $K_{w}=[OH^{-}][H_{3}O^{+}]$ and $K_{w}=1\times10^{-14}$. To calculate the concentration of $OH^{-}$ set the equations equal to each other and plug in the concentration of $H_{3}O^{+}$.
$1\times10^{-14}=(1.2\times10^{-8})[H_{3}O^{+}]$
Rearranging, we get:
$\frac{1\times10^{-14}}{1.2\times10^{-8}}=[H_{3}O^{+}]$ so $[H_{3}O^{+}]=8.3\times10^{-7}$
Since this value for $[OH^{-}]$ is greater than the value for $[H_{3}O^{+}]$, the solution is basic.
