The tutor explores an implication of the definition of pH.

In my Dec 3 post I showed the definition of pH and how to calculate it. What if you know the pH, but want the [H⁺]?

Example 1: Find the [H⁺] of a solution with pH 5.3

Solution:

From the definition of pH

pH=-log[H+]

it follows that, after multiplying both sides by -1,

-pH=log[H+]

Next, we take the antilog (likely shift log or 2nd log on the calculator):

antilog(-pH)=[H+]

In this case, with pH=5.3,

antilog(-5.3)=[H+]

and the calculator yields

5.0×10^(-6)=[H+]

HTH:)

Source:

Hebden, James A. Chemistry: Theory and Problems, Book Two. Toronto: McGraw-Hill Ryerson, 1980.

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.