Chemistry Unit 9 and 10

Question

The pH of the ocean is 8.1. What is the concentration of hydroxide ions?

Answer 1

Hello Jay!

If you know the pH, you can calculate the concentration of H+ ions in a solution.

But we want concentration of OH- ions, so instead we want to use pOH.

pOH = 14 - pH

So the pOH of the ocean is 5.9.

Concentration of OH- can be calculated from pOH with this formula:

pOH = -log[OH^-]

After doing some algebraic manipulation:

[OH-] = 10^-pOH = 10^-5.9 = 1.26 × 10^-6 M