Question

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

Answer 1

pH = 4

Explanation:

To calculate the pH of a solution, use the equation

`pH = -log[H_3O^+]`

Since we are given the hydronium ion (`H_3O^+`) concentration of the solution, we can plug this value into the formula.

`pH = -log[1.00 xx 10^-4 M]`
`pH = 4`

The pH of this solution is 4.

Added notes:
`pH = pH_3O^+` 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[`OH^-`]

`[H^+] = 10^(-pH)`
`[OH^-] = 10^(-pOH)`

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

Hope this helps!