# Help Zone

### Student Question

Secondary IV • 2yr.

Hi again!

What does “ph is measured on a logarithmic scale” mean ????

Chemistry

## Explanations (2)

• Options
Team Alloprof • 2yr.

Hello!

Thank you for counting on us 😉

The logarithm scale of the pH means that between each pH unit, the concentration of hydrogen ions is 10 times greater or 10 times lesser.

Indeed, pH varies according to the concentration of H + ions in a solution. The latter concentration thus varies throughout the scale. When the pH of a solution becomes more acidic, for example, when the pH changes from 4 to 3, the concentration of H + ions increases tenfold. On the contrary, when the pH of a solution becomes more basic,  for example, when the pH changes from 8 to 9, the concentration of H+ ions decreases tenfold.

In this scale, a pH of 1 represents a concentration of 1 x 10 ^ -1 mol / L. As you move up the scale, the concentration becomes 10 times smaller at each level.

• Explanation from Alloprof

Explanation from Alloprof

This Explanation was submitted by a member of the Alloprof team.

Options
Team Alloprof • 2yr.

Hello!

Thank you for counting on us 😉

The logarithm scale of the pH means that between each pH unit, the concentration of hydrogen ions is 10 times greater or 10 times lesser.

Indeed, pH varies according to the concentration of H + ions in a solution. The latter concentration thus varies throughout the scale. When the pH of a solution becomes more acidic, for example, when the pH changes from 4 to 3, the concentration of H + ions increases tenfold. On the contrary, when the pH of a solution becomes more basic,  for example, when the pH changes from 8 to 9, the concentration of H+ ions decreases tenfold.

In this scale, a pH of 1 represents a concentration of 1 x 10 ^ -1 mol / L. As you move up the scale, the concentration becomes 10 times smaller at each level.