An impure sample contains 0.95g of benzoic acid and 0.05 of salicylic acid. Solubilities in water of the two compounds are given in the following table.

Solubility at 20 degrees (g/10mL)
benzoic acid: 0.029
salicylic acid: 0.22

Solubility at 100 degrees (g/10mL)
benzoic acid: 0.680
salicylic acid: 6.67

--> What is the minimum volume of boiling water needed to dissolve the 1.0 g sample?

I'm not sure on what to do. Do I use the solubilities at boiling point for each to find the volumes and then just add the volumes together?

3 answers

Benzoic acid is much less soluble than salicylic acid; therefore, add enough water at the 100 C to dissolve the benzoic acid and the S. A. will take care of itself.
So for the actual calculation.. would i just go 0.95 g benzoic acid * (10mL/0.680 g)?
That's correct.