Problem 2.188

A volume occupied by a saturated vapour is reduced isothermally $n$ -fold. Find what fraction $\eta$ of the final volume is occupied by the liquid phase if the specific volumes of the saturated vapour and the liquid phase differ by $N$ times $(N>n)$. Solve the same problem under the condition that the final volume of the substance corresponds to the midpoint of a horizontal portion of the isothermal line in the diagram $p, V$.