Final answer:
The appropriate flask size for recrystallization depends on the solute involved. Selecting a flask that matches the volume of the solute and solvent ensures proper dissolution and crystallization for the purification process. The option (D) is correct.
Step-by-step explanation:
When asked what size flask you should use for recrystallization. It depends on the solute. During recrystallization, it's crucial to choose a flask that is proportionate to the amount of solute and solvent. A flask too large can result in inefficient heat transfer and undesired solvent evaporation, while a flask too small may not allow for proper dissolution and crystal growth.
The process involves dissolving the solute in a solvent at an elevated temperature and then slowly cooling the solution to allow for the formation of pure crystals. The choice of flask size thus depends on the quantity of solute used, the volume of solvent needed for dissolving, and the temperature at which the solute is soluble in the solvent. Therefore, option (D) is correct.