Question

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?

Answer 1

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.

Answer 2

So for the actual calculation.. would i just go 0.95 g benzoic acid * (10mL/0.680 g)?

Answer 3

That's correct.