A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 \rm torr at 39.9\;^\circ {\rm{C}}.

A solution of methanol and water has a mole fraction of water of 0.312 and a total vapor pressure of 211 rm torr at 39.9;^circ {rm{C}}. The vapor pressures of pure methanol and pure water at this temperature are 256 rm torr and 55.3 rm torr, respectively. Is the solution ideal?