Why is it necessary to rinse the burette with sodium hydroxide before you completely fill it up?

Answer 1

Before a burette is used, it needs to be cleaned. During the cleaning process, usually, water is introduced into the burette. Be the water clean or not, if the burette is then used without rinsing it with the solution that it is going to be filled with, the result of that analytical exercise will not be precise and accurate. The reason is that water residue in the burette would dillute the solution when it's filled in the burette which would make it impossible to determine the exact concentration of the solution moved by the burette. By rinsing and re-rinsing the burette several times with the solution it is going to be filled with, residue water from the cleaning process would be successfully removed from the burette as are other leftover substances from the cleaning process. This practice is quite important as basic analytical technique.

Answer 2

This is to avoid contamination. If the burette were rinsed with water and then filled with the solution, the solution in the burette would be of different concentration than it was filled with.

Answer 3

Sodium hydroxide acts as the titrant in some reactions, particular acid-base reactions where phenolpthalein is used an an inicator of the equivalence point, this is so because phenolpthalein is colourless in acid an pink in base. As the NaOH is titrated against the acid it will easier to see the colour change go from colourless to faint pink rather than from pink to colourless. So to avoid titration errors the NaOh is placed in the burette

Answer 4

so that any residual water or any other solvent used to clean the burette doesn't decrease the original concentration of the solution you want to fill in the burette. hence it is rinsed with the same solution with which it is to be filled

Answer 5

It doesn't necessarily have be rinsed with NaOH, but rather whatever you are going to be putting in there during titration. Is you were going to fill the burette with HCl for example, then you would rinse it with that. It's done in order to stop contamination in your titration, which could lead to impurities and an incorrect titer value.

Answer 6

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Because then you would carry your previous measured solution to your next measuring.

This results in contamination.

In layman's term, contamination = bad

Answer 7

This is to avoid contamination from residue still inside the burette. If another solution is used, that rinsing solution could dilute or contaminate the liquid being tested.

Answer 8

The purpose of this operation is to avoid any contamination of samples.

Answer 9

The burette must be prerinsed with a titrant solution to avoid any contamination.

Answer 10

The purpose is to delete any other impurities.