# What is the hydrogen ion concentration of a solution with pH = 3.75?

$\left[{H}_{3} {O}^{+}\right]$ $=$ ${10}^{- 3.75} \cdot m o l \cdot {L}^{-} 1$
$p H$ $=$ $- {\log}_{10} \left[{H}_{3} {O}^{+}\right]$ by definition.
So we take antilogs, $\left[{H}_{3} {O}^{+}\right] = {10}^{- 3.75}$ $=$ ??