What should you do if you see excess solid at the bottom after stirring?

When there is excess solid at the bottom of a solution after stirring, it indicates that the solution has reached its saturation point and that not all of the solid has dissolved. The presence of undissolved solids suggests that the solution contains more solute than can be accommodated in the solvent at that specific concentration or temperature.

Filtering out the solid is the appropriate action because it allows you to separate the excess undissolved solute from the saturated solution. This process results in a clear solution that contains only the dissolved solute and the solvent, which can be useful for further experimentation or analysis. By filtering, you ensure that any measurements taken or subsequent processes conducted will be based on the correct composition of the solution.

In contrast, simply discarding the solution would mean losing potentially useful dissolved solutes. Stirring more vigorously might not have any effect on the solid material that has already settled and may just introduce air bubbles, which can complicate measurements. Adding more acid could also lead to additional undissolved solids if the solution is already saturated and may not resolve the issue of excess solute.