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