A sample of unknown liquid introduced into a container having volume 250cm3 and vapourised.The weight of the container increased 1.34 g.If pressure in the vessel is 770 mm Hg and temperature is 340 K, calculate the molar mass of the liquid.

Let molar mass of liquid = M.wt.of liquid =1.34 g.∴ no of mol of liquid= wt.  mol  wt .=1.34gM;P=770mm×1atm760mm=7776atm;V=250cm3×1L1000cm3=0.25L;R=0.0821LatmK−mol−,T=340KPV=WMRT (gas equation)∴M=1.34g×0.0821LatmK−mol−×340K×7677atm×0.25L=147.7gmol−