Question

While Prepping for Recrystallization, a hot filtration needs to be performed quickly to avoid crystallization in the glassware.

Identify the appropriate practices you can use to prevent unwanted crystallization. Select one or more:
a. Add a stir bar to the filter paper to stir the sample.
b. Use a short-stemmed funnel in the filtration.
c. Flute the filter paper before heating the funnel.
d. Evaporate some solvent from the sample before filtering.

Answer 1

To avoid crystallization during hot filtration, use a short-stemmed funnel and flute the filter paper before heating. Do not add a stir bar or evaporate solvent before filtration.

Step-by-step explanation:

To prevent unwanted crystallization during hot filtration in the recrystallization process, certain practices can be adopted. It is not advisable to add a stir bar to the filter paper as this doesn't serve a purpose in hot filtration and could disrupt the settling of crystals. However, using a short-stemmed funnel can help reduce the surface area where crystallization can occur and maintain a higher temperature within the funnel to prevent premature crystallization. Also, fluting the filter paper before heating it up enhances the filtration speed by increasing the filter paper's surface area, which helps in preventing the solution from cooling excessively during the process. Evaporating some solvent from the sample before filtering, though, is not recommended as it could lead to supersaturation and thus increase the chances of crystallization in the glassware.