What is a titration?
- Titrations are a method of analysing the concentration of solutions
- Acid-base titrations are one of the most important kinds of titrations
- They can determine exactly how much alkali is needed to neutralise a quantity of acid – and vice versa
- You may be asked to calculate the moles present in a given amount, the concentration or volume required to neutralise an acid or a base
- Titrations can also be used to prepare salts
How to carry out a titration
Performing a titration
Method
- Use the pipette and pipette filler and place exactly 25 cm3 sodium hydroxide solution into the conical flask
- Place the conical flask on a white tile so the tip of the burette is inside the flask
- Add a few drops of a suitable indicator to the solution in the conical flask
- Perform a rough titration by taking the burette reading and running in the solution in 1 – 3 cm3 portions, while swirling the flask vigorously
- Quickly close the tap when the end-point is reached (sharp colour change) and record the volume, placing your eye level with the meniscus
- Now repeat the titration with a fresh batch of sodium hydroxide
- As the rough end-point volume is approached, add the solution from the burette one drop at a time until the indicator just changes colour
- Record the volume to the nearest 0.05 cm3
- Repeat until you achieve two concordant results (two results that are within 0.1 cm3 of each other) to increase accuracy
Results
Results table for a titration
| Rough titre (cm3) | Titre 1 (cm3) | Titre 2 (cm3) | Mean (cm3) |
| 15.50 | 14.90 | 15.00 | 14.95 |
Examiner Tip
Use a funnel to fill the burette but be sure to remove it before starting the practical as it can drip liquid into the burette, making the initial reading false.
