Question

1. why is the buret rinsed with sodium hydroxide solution prior to filling with solution?

Explanation:

When a buret is rinsed with water, some water may remain on the inner walls. If we directly fill it with sodium hydroxide solution, the remaining water will dilute the sodium hydroxide solution, changing its concentration. Rinsing with sodium hydroxide solution first ensures that the solution in the buret has the correct concentration for accurate titration results.

Answer:

To prevent dilution of the sodium hydroxide solution by any residual water in the buret, ensuring the solution in the buret has the correct concentration for accurate experimental results.