Method 1. Fill the burette with dilute hydrochloric acid to just above the 0 cm3
and bring down the level to the 0 cm3 2. Use a pipette to measure 25 cm3
mark. Use the tap to release acid mark.
of sodium hydroxide solution and add to the conical flask.
3. Add two to three drops of methyl orange indicator to the sodium hydroxide solution.
4. Carefully release the acid into the base by opening the tap on the burette.
5. Swirl the conical flask carefully as you add the acid. 6. When the indicator turns from orange to pink stop adding the acid.
7. Read the volume on the burette to find the volume of acid that was added.
8. Repeat the experiment three times and find the average volume of acid that was added.
9. Repeat again without indicator. Add the average volume of acid required to neutralise the base. Use the value you obtained from the previous titrations.
Conical flask
Sodium hydroxide solution and methyl orange indicator
White tile
Fig. 11 Neutralising an acid with a base by titration.
Hydrochloric acid
Burette Retort stand
O. Some unreacted NaOH still in flask so indicator is orange.
HCl has reacted with all the NaOH. Small amount of unreacted HCl in flask. Indicator is pink.
