The mass of a non-volatile solute (molecular mass = 40) which should be dissolved in 114 g octane to reduce its vapour pressure to 80% will be

If p0=100, then ps=80p=p0xA80=100×xAxA=0.80xA=nAnA+nB=114/114114/114+wB/400.8=11+wB/401+wB40=10.8wB=10g                                                    OR                   Po-PsPo= XB 20100=wB40wB40+114114             15=0.025wB1+ 0.025wBwB= 10g