Narration : 5. Titration with a Burette
- Burettes are graduated cylinders that measure the volume of the drained liquid.
- Burettes can be used immediately after rinsing with small amounts of the titration solution to be used.
- Confirm whether the Stopcock is tightly closed.
- Because burettes are considerably tall, you may set them on the floor to transfer a titration solution.
- After setting the funnel, slowly pour the titration solution to an appropriate level.
- After removing the funnel, replace the burette on the bench.
- Next, open the stopcock of the burette to expel the trapped air along with the solution.
- There is no need to adjust the meniscus of the solution to zero.
- Move your eyes to the level of the liquid surface and read the value of the bottom of the meniscus with 1/10 of the smallest scale marked on the burette.
- Add 2 or 3 drops of a phenolphthalein indicator to the sample solution.
- Handle the stopcock with left hand to add the titration solution. Alternatively, one can handle with both hands.
- Shake the vessel to make the sample solution homogenous during the addition.
- Near the endpoint, a part of the sample solution turns red, which disappears soon by mixing.
- The disappearance of the color gradually becomes slow.
- Towards the endpoint, add the titration solution more carefully drop by drop.
- At the endpoint of titration, the faint red color does not disappear.
- The titration value is obtained by subtracting the initial reading from the one at the endpoint.
- This is an inappropriate example of titration. If a judgment is made on the basis of strong color, a correct reading cannot be obtained.
- Wash the used burette, and clamp it upside down on a burette stand leaving the stopcock open.