Answer :
The solvent with the potential to cause oiling out during the recrystallization of a solid with a melting point of 80-82ºC is diethyl ether, due to its low boiling point and high volatility, which can lead to evaporation before crystallization occurs. So, the correct answer is option c. Diethyl ether.
If you wish to recrystallize a solid that has a melting point of 80-82ºC, you should be cautious while selecting a solvent as it influences the recrystallization process. Among the solvents mentioned, the one with the potential of causing the solid to oil out during the recrystallization process is diethyl ether. Oiling out is a phenomenon where the material comes out of solution above its melting point and forms a liquid rather than a solid. This can happen with a solvent that has a relatively low boiling point and is highly volatile, like diethyl ether. The reason for this potential problem is that when a solvent such as diethyl ether is used, it could evaporate too rapidly, leading to an increase in temperature close to the melting point of the solid, causing it to liquify rather than crystallize.
Inappropriate solvent selection might hamper the recrystallization due to quick evaporation and presence of high volatility, as explained in the properties of diethyl ether, acetone, and petroleum ether. Thus, a solvent that is not too volatile and has a moderate boiling point should be preferred, such as ethanol, which is commonly used for crystallization and is less likely to cause oiling out compared to diethyl ether.
So, the correct answer is option c. Diethyl ether.
