Initial Planning

CHEMISTRY
CHEMISTRY LAB 3

Titration

Determination of the reacting volumes of solutions of a strong acid and a strong alkali by titration

Initial Planning

This required practical involves using appropriate apparatus to make and record a range of measurements accurately, including volume of liquids. It also involves determining the concentration of one of the solutions in mol/dm³ and g/dm³. 

Aims

• To determine the reacting volumes of solutions of an acid and alkali by titration.
• To determine the concentration of one of the solutions in mol/dm³ and g/dm³.

Apparatus

Read these instructions carefully before you start work.

METHOD

1. Use the pipette and pipette filler to add a measured volume (25 cm³) of sodium hydroxide solution to a clean conical flask.
2. Add a few drops of indicator and put the conical flask on a white tile.
3. Fill the burette with hydrochloric acid and note the starting volume.
4. Slowly add the acid from the burette to the alkali in the conical flask, swirling to mix.
5. Stop adding the acid when the end-point is reached (when the indicator first permanently changes colour). Note the final volume reading.
6. Repeat steps 1 to 5 until concordant titres are obtained. More accurate results are obtained if acid is added drop by drop near to the end-point.

RESULTS

 

Evaluating the practical

The evaluation should address these points:

• What actions were taken to make accurate measurements?
• What improvements could be made to the method?
• Was the practical carried out safely? What improvements could be made?

Health, safety and technical notes