Experiment: To make up an approximate solution of sodium hydroxide and standardise it (find its exact concentration) by titration with the standard hydrochloric acid solution above.
Procedure
- Place 20 ml of the sodium hydroxide in the conical flask. Note: Always place the base in the conical flask as they may react with the ground glass in the tap of the burette.
- Add two drops of methyl red indicator and a yellow colour is imparted to the solution.
- Put the hydrochloric acid (previously standardised) into the burette. Adjust to the zero level in the usual way.
- Titrate in the usual manner.
- When the colour of the solution in the conical flask changes to a faint trace of permanent pink the end-point has been reached.
- Record the volume of acid required to do this.
- Repeat the titration several times until two titration values agree to within 0.2 ml of each other.
Equation for the titration
Results
- Volume of base = 20 ml
- Factor for the base = 1
- Molarity of the base = ?
- Volume of the acid = 19.8 ml
- Factor for the acid = 1
- Molarity of the acid = 0.1 M
Calculations
