What is the minimum volume of boiling water needed to dissolve 0.200 g of sodium benzoate? The solubility of sodium benzoate in boiling water is 1 gram per 1.4 mL. About how much sodium benzoate will remain dissolved when the water is cooled to 25C ? The solubility of sodium benzoate at 25C is 1 gram per 1.8 mL. Calculate the maximum mass of solid sodium benzoate that can be recovered when the cooled solution is filtered. In some cases, mixed solvents are used for recrystallization. What would be the purpose of using a mixed solvent? 8. a. Explain why the melting point of pure phthalic acid is higher than that of pure naphthalene, when the two compounds have nearly the same molecular weight.