Question

When you'll transfer a 35 ml solution using a 50 ml burette, what are your sources of errors? Room temperature? Tapering end of the burette? Any clue?

Answer 1

The possible sources of error that can occur while transferring solution from a burette are :

1. the most commonly committed error is PARALLAX ERROR - the scale of the burette should ALWAYS be viewed from the prependicular line at the meniscus. if you observe the meniscus from below the perpendicular line , the meniscus might appear above from the point where it actually lies. similarly observing it from above the perpendicular line will make you record the point below from where it actually lies.

2. Airlock in the stopcock or the burette tip can cause you to take a lesser /higher volume of the solution out of the burette

3. Many students often forget to remove the funnel from the top of the burette after transferring the solution in the burette.This increases the air pressure inside the burette as a result the volume of each drop falling down may vary.

4. Running the burette too fast or too slow (drop by drop) can bring a change in the volume of each drop.

5.The least count of the burette should be carefully recorded and should be kept in mind while transferring the solution.

Temperature can also cause an error while using burette for measuring solutions as too high temperature can bring an expansion to the burette glass and change the volume of the mentioned scales.thus the optimum temperature for use is always measured on the burettes

Yes ,Tampering end of the burette may vary the drop volume .Also while you are running down the solution, solution may linger on the side walls of the end and hamper the volume required.