Equilibrium digram for H2O-Ethanol mixtures. Adding alcohol to water lowers the boiling temperature of the solution. The lower, curved boiling line on this diagram gives the temperature of boiling (saturation with vapor) for each solution composition (weight percent alcohol). The chemical composition of the vapor that boils from the solution is given by the upper, curved condensation line (saturation with liquid) at the same temperature. The vapor is much richer in alcohol than the boiling liquid. The two-phase area between the two saturation curves has example tie lines that connect the compositions of the liquid and vapor at equilibrium at the temperature of the tie line. Click the "Show Phase %" button and mouseover the diagram to see the proportions of liquid and vapor for each bulk composition and temperature. The two curves meet at 95.6% alcohol and 78.17°C, an azeotropic point. Data from Evans (1916).
Wt.% CH3CH2OH:
Temperature:
Wt.% Vapor:
Vap:
Wt.% Liq:
Liq:
