For Phase Equilibria
\( T_\text{liq} = T_\text{vap} \)
\( p_\text{liq} = p_\text{vap} \)
\( f^\text{liq} = f^\text{vap} \)
Relative Volatility
\( K_i = \frac{y_i}{x_i} \)
\( \alpha_{ij} = \frac{K_i}{K_j} \)
Eutectic
\( L \rightarrow \alpha(s) + \beta(s) \)
Peritectic
\( \alpha(s) + L \rightarrow \beta(s) \)
Azeotrope
\( y_i = x_i\)
At an azeotrope the vapour and liquid compositions are the same. Therefor, the components can’t be separated by distillation
\( dG_i = RT d\left( \ln \hat{f_i} \right), \quad \lim_{p \to 0} \left( \frac{\hat{f_i}}{x_i p} \right) = 1\)