1. pH

2. pH
The strength of an acid or base is measured using a scale called pH.
pH stands for ‘power of Hydrogen’
pH scale ranges from 0-14
Acids have a pH less than 7
Bases have a pH higher than 7
Neutral pH is 7

3. Acids and Bases are actually related.
Weak acid = Strong base
Strong acid = Weak base

4. Weak & Strong
pH Measures the concentration of H+ available in water. The higher the concentration, the more acidic the solution is. The scale is exponential. pH 7 has a 1 to 1 ratio of H+: OH- pH 6 = 10x concentration of pH 7. pH 5 = 10x concentration of pH6. 1

5. pH Indicators
pH indicators are chemical compounds which change colour depending on the concentration of H+
Examples:
Litmus
Thymol blue
Phenolphthalene
Bromothymol blue
Methyl Orange

6. Why measure pH? We use pH indicators to measure a variety of things:
pH of Swimming pools
Waterways and environment
pH in the garden, soil.
Stomach conditions, skin, hair and mouth