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.


  • 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


  • 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