Question

The solubility of an active pharmaceutical ingredient Z in water-acetone mixtures has been determined experimentally at 298 K and the resulting data can be expressed as Cs = 0.002(1+ 15 xA 2.5), where the saturation composition Cs has units of kg of Z per kg of solvent mixture and xA is the mass fraction of acetone in the solvent mixture. Molar masses: Z: 236 g/mol; acetone: 58.1 g/mol; water: 18.0 g/mol. A saturated solution of Z in acetone was prepared at 298 K. A supersaturated solution was then prepared by mixing 1000 kg of the solution with 2000 kg of water. Using the solubility data given above, calculate the saturation concentration of Z in the resulting mixture and the corresponding relative supersaturation.

Answer 1