Difficulties with equipment
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Depending on the size of the class and amount and quality of laboratory glassware available, teachers may find that they have to rethink the class practical activities if sufficient, properly working, burettes aren't available.
What could you do if there are insufficient burettes?
Students could experiment with the principles of titrations by using a simplified method of counting drops or aliquots of acid or alkali.
For example, the student has a measured volume of a known alkali in a conical flask with a little indicator and adds drops or aliquots of the acid, eg 1 cm3 volumes delivered from a 1 cm3 disposable pipette. The indicator will show the end point and the student can note the volume of acid added. This may be a useful exercise in developing understanding of titrations anyway, before more accurate measurements are introduced. The accuracy and sources or errors could be discussed.
Is there anything more like a burette, but more economical?
Using a micro burette can be a good method of 'micro titration' experiment – a small-scale titration. It will also use far smaller volumes of all reagents.
A micro burette can be made from a graduated glass pipette, some soft tubing and a disposable syringe by following these instructions. The simple titration of an acid and an alkali can be followed from this procedure. The learning outcomes will be very similar to a full-scale burette, including the opportunity to use concentrations, volumes, apply balanced equations and to determine the unknown concentration of an acid or an alkali.
What about problems with an existing class set of burettes?
Keeping burettes clean and free from dust will go a long way to preventing many problems. If you notice that droplets of water or solutions are clinging to the inside of the burette when the bulk of the solution has run down, it's time to give the burette a good clean with detergent to get rid of any grease or dirt that is the cause. The burette should then be rinsed out thoroughly with water and rinsed with distilled water.