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Sah eee a2 Tn. PROBLEMS IN PHYSICAL CHEMISTRY oa, , 19. Two liquids A and B form ideal solutions. At 300 K, the vapour pressure of solution containing, 1 mole of A and 3 mole of B is 550 mm Hg. At the same temperature, if one more mole of B is, added to this solution, the vapour pressure of the solution increases by 10 mm Hg. Determine, the vapour pressure of A and B in their pure states (in mm Hg):, , (a) 400, 600 (b) 500, 500 {c) 600, 400 (d) None of these, , 20. ‘Iwo liquids A and B have vapour pressure in the ratio Py : Pg =1:3 ata certain temperature., Assume A and B form an ideal solution and the ratio of mole fractions of A to B in the vapour, phase is 4 : 3, then the mole fraction of B in the solution at the same temperature is :, , z 2 4 £, (a) = (b) . () <q (d) 4, , , , , , , 21. Two liquids A and B have P? and P@ in the ratio of 1: 3 and the ratio of number of moles of A, and B in liquid phase are 1 : 3. Then mole fraction of ‘A in vapour phase in equilibrium with, the solution is equal to:, , (a) 0.1 (b) 0.2 {c) 0.5 (d) 1.0, , 22. Based on the given diagram, which of the following statements regarding the homogenous, , solutions of two volatile liquids are correct?, , iD, c H, vel, é, 8, , AE mole fraction, X= Xq=1, (1) Plots AD and BC show that Raoult’s law is obeyed for the solution in which B is a solvent, and A is the solute and as well as for that in which A is solvent and B is solute., (2) Plot CD shows that Dalton’s law of partial pressures is obeyed by the binary solution of, components A and B., (3) EF + EG =EH; and AC and BD correspond to the vapour pressures of the pure solvents A, , and B respectively., , , , , , , , , , , , , , , , , , , , , , (a) Only 1 (b) 2 and 3 (c) land 3 (d) All, 23. Which represents correct difference when non -volatile solute is present in an ideal solution?, ;>———Vapour, AS), (as) (83) souution : (yy (ay = (aH), Solvent Solutior Solvent, ——— Soivent or Solution, ~ Solvent, Solution, BP., (hy, Solvent, , , , , , (a) 1, 0, Ul (b) 1, Wl (c) U1, Ut () Lt

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Hy OLwte soumron aaa aaa : Ce, , 24,, , 26., , 27., , Select correct statement :, , (a) Solution has more molecular randomness than a, between solution and solid is larger than the entro;, solid, , (b) Heat of fusion of solution and solvent are similar since similar forces of intermolecular, forces are involved, , {c) Solution containing sugar freezes at a lower temperature than pure water, , (d) All are correct statements, , Select correct statement?, , (a) Heats of vaporisation for a pure solvent and for a solution are similar because similar, intermolecular forces between solvent molecules must be overcome in both cases, , (b) Entropy change between solution and vapour is smaller than the entropy change between, pure solvent and vapour, , (c) Boiling point of the solution is larger than that of the pure solvent, , (d) All are correct statements, , The vapour pressure curves of the same solute in the same solvent are shown below. The, , curves are parallel to each other and do not intersect. The concentrations of solutions are in, , order of:, , Pure solvent, The entropy change, Py change between pure solvent and, , C4, + see wiih, + Tamperature, fail<u< (bj) l=l=m ()1>0>M (dd) I>Mm>u, , Boiling point composition diagram of the liquid-vapour equilibrium for A and B is shown in the, figure. If a binary liquid mixture of A and B is distilled fractionally, which of the following, would be correct observation?, , , , X,~1 % Composition Xg= 1, (a) Composition of the still (residue) will ee pure liquid B, sition of the distillate will approach pure A ;, i cane of distillate and residue will approach pure A and B respectively, i : nent can be obtained in pure state, S een re = coenople mixture of water—ethanol is less than that of both water and, a arena will show negative deviation from Raoule’s law, (b) the mixture will show positive deviation from Raoult 's law, (c) the mixture will show no deviation from Raoult's law, (d) this mixture cannot be considered as true solution