Critical anomalies and phase diagrams of a binary mixture

The study examines the behavior of a binary mixture in the vicinity of the liquid–vapor critical point. It is shown that the pressure dependence on density along the critical isotherm, predicted within the framework of the existing theory of critical phenomena, does not match the shape of the dew-bubble curves. The problem is analyzed with the equation of state for a multicomponent near-critical mixture, adapted to describe thermophysical properties of a binary mixture. To eliminate the problem it is proposed to impose an additional condition on the equation of state coefficient. Possible consequences of imposing such a condition are considered.