If the solubilities of different components (in a liquid-liquid extraction system) increase with rise in temperature, then the temperature above which they dissolve completely is known as the critical solution temperature (CST or consolute temperature). If solubilities increase with decrease in temperature, then CST is the temperature below which they dissolve completely. If a binary system has no critical solution temperature, it implies that

• A. The system comprises of miscible liquids
• B. On heating, a vapor phase will appear ; while on cooling, a solid phase will appear
• C. The system comprises of partially mis-cible liquids
• D. The system comprises of an azeotrope

Answer: (B)