# Definition of pH scale in Chemistry

The pH scale in Chemistry represent values with specific color.

The **pH is the degree of acidity or basicity of a chemical substance in aqueous systems.**

In simple terms pH is the power of hydrogen ion or hydronium ion concentration.

It can be calculated by :

## The pH scale by Equation

pH = – log_{10}[H^{+}] or

pH = – log_{10}[H_{3}O^{+}]

[ ] square bracket represents the concentration in mol/dm^{3}

Example: If a sample of an acid is found to have[ H^{+}]=1X10^{-4}

Than pH = – log_{10}[1X10^{-4}]

pH = -[-4 log 10]

pH= 4

### H^{+} Concentration Formula

If you want to find out [ H^{+}] than you can use the following formula:

H^{+} concentration = 10^{-pH}

Find `Data Booklet`