A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is Φi yi P = Yi xi fi° where, Φ is a vapor fugacity component, Yi is the liquid activity co-efficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of

• A. Temperature, pressure and liquid composition xi only
• B. Temperature only
• C. Temperature, pressure, liquid composition xi and vapour composition yi
• D. Temperature and pressure only

Answer: (A)