The amount of Glucose to be dissolved in 500g of water so as to produce the same lowering in vapour pressure as that of 0.2 molal aqueous urea solution will be

Urea solution and glucose solutions have same lowering of VP.It means that both the solutions must have same concentration.(both Urea sol and glucose sol. neither associates nor dissociates)Given,   molality of Urea sol =0.2mmolality of glucose sol. must be 0.2m∴WH2O=500g  0.2=Wglucose 180X1000500Wglucose=18g