This interactive diagram illustrates the Vapor-Liquid Equilibrium (VLE) for an **Ethanol-Water** binary mixture based on **Raoult’s Law modified with the Margules activity coefficient model**. This approach provides a more rigorous thermodynamic representation compared to empirical functions.

• The blue line represents the **Liquid Phase (Boiling Point Curve)**: Shows the boiling temperature of the liquid mixture at different compositions, calculated where total pressure equals atmospheric pressure.
• The red line represents the **Vapor Phase (Dew Point Curve)**: Shows the composition of the vapor in equilibrium with the boiling liquid at that temperature.
• The purple dot(s) mark the **Azeotropic Point(s)**: The composition(s) where the liquid and vapor phases have the same mole fraction ($y_A = x_A$), meaning the mixture boils at a constant temperature without changing composition.

Mole fraction of Ethanol (Component A) on the X-axis. Water is Component B.

*This simulation uses fixed Antoine coefficients for Ethanol and Water and a simplified symmetric one-parameter Margules equation for activity coefficients. A numerical bisection method is used to solve for boiling temperatures.*