Give me answer of this question. The vapour pressure of benzene at a certain temperature is 640mm of Hg. A non-volatile and non-electrolyte solid weighing 2.175g is added to 39.08g of benzene. The vapour pressure of the solution is 600,mm of Hg . What is the molecular weight of solid substance: (a) 49.50 (b) 59.6 (c) 69.5 (d) 79.8