# What is the pH of a solution that has a hydronium ion concentration of 1.00 times 10^-4 M?

Jun 28, 2017

pH = 4

#### Explanation:

To calculate the pH of a solution, use the equation

$p H = - \log \left[{H}_{3} {O}^{+}\right]$

Since we are given the hydronium ion (${H}_{3} {O}^{+}$) concentration of the solution, we can plug this value into the formula.

$p H = - \log \left[1.00 \times {10}^{-} 4 M\right]$
$p H = 4$

The pH of this solution is 4.

$p H = p {H}_{3} {O}^{+}$ because hydrogen ions attach to water molecules for form hydronium ions.

Some other key things to remember for pH calculations include:

pH + pOH = 14

pH = -log[${H}^{+}$]
pOH = -log[$O {H}^{-}$]

$\left[{H}^{+}\right] = {10}^{- p H}$
$\left[O {H}^{-}\right] = {10}^{- p O H}$

The video below explains how to use all this information so that you can complete these types of calculations.

Hope this helps!