PH is the degree of acidity or basicity of a solvent.
PH values ranging from 0 to 14. A solution is neutral when it’s pH value = 7. pH value > 7 indicates the solvent is in basicity condition, while if the pH value <7 indicate the solvent is in acid condition. The name pH comes from potential of hydrogen.
Simple indicator generally used to check pH value is the litmus paper. If the litmus color changes to red, it indicates that the acidity is high; and if the litmus color is blue, it indicate that the basicity is high.
Beside of using litmus paper, we can use pH meters that work based on the principle of electrolyte of solution.
How to measure pH of activated bleaching earth is as follow:
1. Weigh fullers earth as much as 5 grams.
2. Mix with pure water 50 ml.
3. Stir mixture of fuller’s earth and water until they mix up.
4. Put into the mixture litmus paper or pH meters. See the color of litmus paper or pH meter reading results.
5. Normal activated bleaching earth has pH value = 3 or 3.5. If fullers earth pH value <3 it means that the fuller’s earth isn’t wash until clean from acid sulphate when activated. It makes damage or corrosive in the refinery process machines.