In the experiment "Preparation and Standardization of a Sodium Hydroxide Solution", why was the burette rinsed with NaOH before filling it to "zero" for the titration?

The correct option is ALL OF THE ABOVE.

Explanation:

TITRATION is a type of volumetric analysis which is used for determining the concentration of solutions. In this process a specific volume of a solution is placed in a conical flask by means of a pipette and small quantities of a second solution is slowly added from a burette until the end point is reached. This is determined by a means of an indicator which shows a characteristic colour change.

During titration, the following precautions should be followed to avoid errors and maintain standardisation in the experiment.

--> Any air bubble in the burette and pipette must be removed during measurement

--> the burette tap should be tightened to avoid leakage.

--> Remove the funnel from the burette before taking any reading to avoid errors in reading the volume.

--> use the base solution such as Sodium Hydroxide Solution to rinse the burette after washing with soap and tap water:

• to remove any air bubble and fill it's tip

• to remove any residual liquid from the water and soap solution which may interfere with the results of the experiment.

• to check if the burette is in good condition.

Therefore all of the above options to the question are correct.

c (diamond),

sio2 (quartz)