4.9 describe experiments to carry out acid-alkali titrations.

Acid-alkali titrations

A titration is a method of finding out exactly the volume of one solution that is required to react with a given volume of another solution.

Titrations are commonly used to find out the volume of acid required to react exactly with a given volume of an alkali:

1. Using a pipette, put 25.0cm3 of an alkali solution into a conical flask.
2. Add a few drops of an indicator, such as methyl orange.
3. Put the acid in a pipette and note the initial reading.
4. Add the acid to the alkali until the indicator just changes colour.
5. Not the final reading of acid in the burette.
6. Subtract the initial reading to obtain the volume of acid added. This is the volume required to neutralise the 25.0cm3 of the alkali.