Question

On heating 25g of a saturated solution to dryness at 60oc, 4g of anhydrous salt was recovered. Calculate its solubility in grams per 100g of solvent

Answer 1

You had 25 g solution and obtained 4g anhydrous salt; therefore, you must have had 21 g H2O. So the saturated solution was 4g/21g solvent. Convert to g/100 mL.
4g salt x (100/21) = ?

Answer 2

19.0476