* Dissolve sodium benzoate well at high temperatures: The solvent should be able to dissolve a significant amount of sodium benzoate when heated, allowing for a concentrated solution.
* Poorly dissolve sodium benzoate at low temperatures: As the solution cools, the solubility of sodium benzoate should decrease significantly, leading to crystal formation.
* Not react with sodium benzoate: The solvent should not react with sodium benzoate under the recrystallization conditions.
* Easy to evaporate: After crystallization, the solvent should be easily evaporated to recover the pure sodium benzoate crystals.
Based on these criteria, water is a very good solvent for recrystallization of sodium benzoate.
Here's why:
* High solubility at high temperatures: Sodium benzoate is quite soluble in hot water.
* Low solubility at low temperatures: The solubility of sodium benzoate in water decreases significantly as the temperature drops.
* No reaction: Water does not react with sodium benzoate under normal conditions.
* Easy to evaporate: Water evaporates readily, leaving behind the pure sodium benzoate crystals.
Other solvents that might work:
* Ethanol: Ethanol can also be used for recrystallization of sodium benzoate, but it might require a higher temperature to achieve sufficient solubility.
* Methanol: Methanol can also be used, but it is more volatile and flammable than ethanol and water, requiring careful handling.
Important note: It's always a good idea to perform a small-scale trial recrystallization with the chosen solvent to optimize the conditions and ensure successful purification.
