The relative lowering of vapour pressure of 0.2 molal solution in which the solvent is Benzene is

molality of sol. =0.2mNo.of moles of solute =0.2wt. of solvent (Benzene)=1000g no.ofmoles of Benzene =100078relative lowering of VP of sol. of non volatile solute,(RLVP)Po-PPo=Xs=mm+1000GMWof solvent  where , m=molality∴RLVP=0.20.2+100078=15.6X10-3