# A certain solution has a hydrogen ion concentration of 0.000589 moles per liter. What is this number in scientific notation?

Well, it is $5.89 \times {10}^{-} 4 \cdot m o l \cdot {L}^{-} 1$...
We can extend this, and provide a definition of $p H$: $p H = - {\log}_{10} \left[{H}_{3} {O}^{+}\right] = - {\log}_{10} \left(5.89 \times {10}^{-} 4\right) = - \left(- 3.23\right) = 3.23$.
And we know that in aqueous solution $p H + p O H = 14$. So what is $p O H$, and $\left[H {O}^{-}\right]$ here?