At 25 oc the vapour in equilibrium with a solution containing carbon disulfide (cs2) and acetonitrile (ch3cn) has a total pressure of 263 torr and is 85.5 mole percent carbon disulfide. what is the mole fraction of carbon disulfide in the solution? at 25 oc the vapour pressure of carbon disulfide is 375 torr. assume that the solution and the vapour exhibit ideal behaviour.