How do you calculate the pH of HCl?

1 Answer

To calculate the pH of HCl you need to know the concentration expressed in molarity (mol HCl/L solution). You will use the following equation to find the pH.

pH = -log[H+]

This means you take the negative log of the hydrogen ion concentration to find the pH.

The hydrogen ion concentration is the same as the concentration of the acid because HCl is a strong acid and dissociates as follows:

HCl -> #H^+# + #Cl^-# (notice the 1:1 ratio of HCl and #H^+#)

A 1M HCl solution has a pH of 0
A 0.1M HCl solution has a pH of 1
a 0.01M HCl solution has a pH of 2

This video discusses additional examples

Noel P.