3 BaCl + 2 Na PO Ba PO + 6 NaCl

Transcription

1 Q. No. 1 In which mode of expression, the concentration of solution remains independent of temperature? Molarity Normality Formality Molality Explanation Molality because molality involves mass which is independent of temperature of solvent. Q. No. 2 If 0.50 mole of BaCl 2 is mixed with 0.20 mole of Na 3 O 4, the maximum number of moles of Ba 3 (O 4 ) 2 that can be formed is BaCl + 2 Na O Ba O + 6 NaCl Explanation L.R. BO O 0.1 moles Q. No. 3 The normality of 10 % (weight / volume) acetic acid is 1 N 10 N 1.7 N 0.83 N Explanation 10 Number of moles = 60 Volume of solution = 100 ml = 0.1 L V. f. of CH 3 COOH = 1 N = M V.f 10 = 1 = 1.7 N 60 Q. No ml of solution is neutralized by 15 ml of 0.2 N base. The strength of the acid solution is 0.1 N 0.15 N 0.3 N 0.4 N Explanation Number of eq of base = number of eq of acid = 30 x x = 0.1 N

2 Q. No. 5 The formula weight of H 2 SO 4 is 98. The weight of the acid in 400 ml of 0.1 M solution is 2.45 g 3.92 g 4.90 g 9.8 g Explanation 400 ml 0.1 M = 0.04 moles = = 3.92 g Q. No ml of 3N-HCl, 20 ml of N 2 H 2SO 4 and 30 ml of N 3 HNO 3 are mixed together and volume made to one litre. The normality of the resulting solution is N 2 N 10 N 20 N 40 Explanation N N final = = N = 20 Q. No. 7 To 5.85 g of NaCl, one kg of water is added to prepare a solution. What is the strength of NaCl in this solution? (Molecular weight of NaCl = 58.5) 0.1 Normal 0.1 Molal 0.1 Molar 0.1 Formal Explanation 0.1 Molal Q. No. 8 What is the normality of a 1 M solution of H 3 O 4? 0.5 N 1.0 N 2.0 N 3.0 N Explanation + 3- H3O 4 3H + O4 V.f = 3 N = M 3 = 3.0 N Q. No. 9 The normality of a 2.3 M sulphuric acid solution is 0.46 N

3 0.23 N 2.3 N 4.6 N Explanation V.f. of H 2 SO 4 = 2 N = = 4.6 N Q. No ml of 0.2 N HCl, 50 ml of 0.1 NH 2 SO 4 and 100 ml 0.2 N HNO 3 are mixed. The normality of resulting solution is 0.10 N 0.15 N N 0.20 N Explanation N final = = = N 200 Q. No. 11 In a solution of 7.8 g of benzene (C 6 H 6 ) and 46 g of toluene (C 6 H 5 CH 3 ), the mole fraction of benzene is Explanation 7.8 Number of moles of C6H 6 = = Number of moles of C6H5 CH 3 = = Total moles = C6H 6 = = Q. No. 12 The molarity of a solution of Na 2 CO 3 having 10.6 g 500 ml 0.2 M 2 M 20 M 0.02 M Explanation 10.6 M = = 0.2 M ml of solution is

4 Q. No. 13 Molarity of a solution containing 1 g NaOH in 250 ml of solution is 0.1 M 1 M 0.01 M M Explanation 1 M = 40 = 0.1 M 0.25 Q. No. 14 Which one of the following solutions of sulphuric acid will exactly neutralize 25 ml of 0.2 M sodium hydroxide solution? 12.5 ml of 0.1 M solution 25 ml of 0.1 M solution 25 ml of 0.2 M solution 50 ml of 0.2 M solution Explanation 2 moles of NaOH are neutralized by 1 mole of H 2 SO = number of H 2 SO 4 moles 2 = Q. No. 15 Assertion : The sum of mole fractions of all components of a solution is unity. Reason : Mole fraction is independent of temperature. If both Assertion & Reason are true and the reason is the correct explanation of the assertion If both Assertion & Reason but true and the reason is not the correct explanation of the assertion If assertion is true statement but Reason is false If both Assertion and Reason are false statement Explanation Both are true but reason is not correct explanation for it. Q. No. 16 A solution is prepared containing a 2 : 1 mol ratio of dibromo ethane (C 2 H 4 Br 2 ) and dibromo propane (C 3 H 6 Br 2 ) what is the total vapour pressure over the solution assuming ideal behavior? Vapour pressure (mm Hg) C 2 H 4 Br C 3 H 6 Br mm Hg 158 mm Hg 150 mm Hg 142 mm Hg Explanation Final vapour pressure = = 158 mm of Hg Q. No. 17 Which of the following graphs represent the behavior of ideal binary liquid mixture?

5 1 lot of Total 1 lot of Total against y is linear A against y is non-linear lot of Total against y A is linear lot of Total against y B is linear Explanation 0 A x A = Total ya For a ideal binary liquid the value is fixed. 1 against y A is linear Total B Q. No. 18 Mixture of volatile components A and B has total vapour pressure (in torr) : = X A Where, X A is mole fraction of A in mixture. Hence A 0 and 0 B are (in torr) : 254, , , , 119 Explanation 0 0 T = A X A + B XB X = 1 - X B A 0 0 = X x T A A B A 0 B 0 0 A B 0 A = 254 = = X A B A B = X A - = -119 = 135 Q. No. 19 The plot of 1 y A A - and A B 0 0 B B A - and B A 0 0 B B B - and A B 0 0 A A B - and B A 0 0 A B Explanation 0 x = y A A T A against 1 x A is linear with slope and intercept respectively :

6 A y = x T A A x 0 A A B A B = A A xa A A B A B and intercept is 0 0 A A 1 y x Slope is Q. No. 20 If A is the vapour pressure of a pure liquid A and the mole fraction of A in the mixture of two liquids A and B is x, the partial vapour pressure of A is : (1 - x) A x A x 1 - x A 1 - x x Explanation x A A Q. No. 21 Which statement about the composition of vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume the temperature is constant at 25 0 C. Vapour pressure data (25 0 C) : Benzene 75 mm Hg Toluene 22 mm Hg The vapour will contain higher percentage of benzene The vapour will contain higher percentage of toluene The vapour will contain equal amount of benzene and toluene Not enough information is given to make a prediction Explanation T = = = = T yc H y = 75 CH y = 22 CH y > y C 6 H 6 C 7 H 8 Q. No ml of a liquid A was mixed with 25 ml of a liquid B to give a non-ideal solution of A- B mixture. The volume of this mixture would be 75 ml 125 ml Close to 125 ml Just more than 125 ml Explanation Because of non-ideal solutions.

7 Q. No. 23 A mixture of benzene and toluene forms An ideal solution Non-ideal solution Suspension Emulsion Explanation An ideal solution Q. No. 24 Which of the following liquid pairs shows a positive deviation from Raoult s law? Water-hydrochloric acid Water-nitric acid Acetone-chloroform Benzene-methanol Explanation Q. No. 25 Which of the following pairs shows a negative deviation from Raoult s law? Acetone-benzene Acetone-ethanol Acetone-chloroform Benzene-methanol Explanation Acetone-chloroform Q. No. 26 An azeotropic solution of two liquids has boiling point lower than either of them when it Shows a negative deviation from Raoult s law Shows no deviation from Raoult s law Shows positive deviation from Raoult s law Is saturated Explanation Shows positive deviation from Raoult s law Q. No. 27 Which of the following statements is correct for a binary solution? A solution in which heat is evolved exhibits positive deviations from Raoult s law. A solution in which heat is absorbed shows negative deviations from Raoult s law. When one component in solution shows negative deviation from Raoult s law, the other exhibits positive deviation. When one component in solution shows positive deviation from Raoult s law, so does the other. Explanation Conceptual. Q. No. 28 Which one of the following pairs will not form an ideal solution? Benzene and toluene Chloroform and acetone 2-Methyl propanol and 2-propanol Ethylene bromide and propylene bromide

8 Explanation It shows -ve deviation. Q. No. 29 The diagram given below is a vapour pressure-composition diagram for a binary solution of A and B. In the solution, A-B interactions are Similar to A-A and B-B interactions Greater than A-A and B-B interactions Smaller than A-A and B-B interactions Unpredictable Explanation For + ve deviation A-B < A-A and B-B. Q. No. 30 A binary liquids mixture of two liquid A and B showing the departure from the ideal behaviour : Behaves as an ideal solution of B into A when X 0 B Behaves as an ideal solution of A into B when X 0 H Soln A is always positive T S Soln is always positive Explanation Conceptual. Q. No. 31 Which pair (s) of liquids on mixing are expected to show no net volume change and no heat effect Acetone and ethanol Chlorobenzene and bromobenzene Chloroform and benzene n-butyl chloride and n-butyl bromide. Explanation Ideal solution. Q. No. 32 Composition of an azeotrope Is independent of external pressure because it is a compound Alters on changing the external pressure Remains unchanged during distillation at a constant external pressure Fluctuates even at constant pressure Explanation Conceptual. Q. No. 33 In binary liquid mixture of components, A and B, the former has greater tendency to escape into the vapour state than demanded by Raoult s law. Indicated the correct statement(s)

9 Component A shows positive deviation and the component B negative deviation Both component show positive deviations Component A shows negative deviation and the component B positive deviation The component B has also greater tendency to escape into the vapour state than demanded by Raoult s law Explanation Both show + ve deviation. Q. No. 34 The solution showing positive deviation Have V (mixing) = +ve Have H (mixing) = -ve Form minimum boiling azeotropes. Have lower vapour pressure of each component in the solution than their pure vapour pressure. Explanation + ve has V = + ve Η = + ve minimum boiling azeotropes. Q. No. 35 Assertion : Hmix and Vmix are zero for the ideal solution. Reason : The interactions between the particle of the components of a solution are almost identical as between particles in the liquids. If both Assertion & Reason are true and the reason is the correct explanation of the assertion If both Assertion & Reason but true and the reason is not the correct explanation of the assertion If assertion is true statement but Reason is false If both Assertion and Reason are false statement Explanation If both Assertion & Reason are true and the reason is the correct explanation of the assertion Q. No. 36 The millimoles of N 2 gas that will dissolve in 1L of water at 298 K. when it is bubbled through water and has a partial pressure of 0.96 bar will be (Given that at 298 K K H = 76.8 k bar) Explanation 0.96 x = x + 18 x = x x = 0.69 Q. No. 37 Air contains O 2 and N 2 in the ratio of 1 : 4. The ratio of their solubilities in terms of mole fractions at atmospheric pressure and room temperature will be (Given Henry s 1 : constant for O = torr, for N = torr )

10 2 : 1 4 : 1 1 : 4 Explanation 1 1 = 4 2 T = KhXo2 1 KO X = L 4 K X OL NL N2 1 1 X = 4 2 X KOL 1 = X 2 NL O2 N2 Q. No. 38 Colligative properties of the solution depend on Nature of solute Nature of solvent Number of solute particles present in the solution Number of moles of solvent only Explanation Colligative properties of the solution depend on nature of solvent and number of solute particles present in the solution Q. No. 39 Which one is colligative property? Boiling point Vapour pressure Osmotic pressure Freezing point Explanation Osmotic pressure Q. No. 40 The relative lowering of the vapour pressure is equal to the ratio between the number of Solute molecules to the solvent molecules Solute molecules to the total molecules in the solution Solvent molecules to the total molecules in the solution Solvent molecules to the total number of ions of the solute Explanation Solute molecules to the total molecules in the solution Q. No. 41 Vapour pressure of a solution of non-volatile solute is Directly proportional to the mole fraction of the solvent Independent of mole fraction of the solute Inversely proportional to the mole fraction of the solvent Directly proportional to the mole fraction of the solute Explanation Directly proportional to the mole fraction of the solvent

11 Q. No. 42 Vapour pressure of a solution of 5 g of non-electrolyte is 100 g of water at a particular temperature is 2985 N/m 2. The vapour pressure of pure water is 3000 N/m 2, the molecular weight of the solute is Explanation WM A B 5 18 M A = = = W 100 B 3000 B Q. No. 43 The vapour pressure of benzene at a certain temperature is 640 mm Hg. A nonvolatile electrolyte solute weighing g is added to g of benzene. If the vapour pressure of the solution is 600 mm of Hg, what is the molecular weight of the solid substance? Explanation M A = = Q. No. 44 Which of the following is are correct statements (s) about the Raoult s law applied to a solution of non-volatile solute. Vapour pressure of solution is proportional to mole fraction of solute V.. of solution is proportional to the mole fraction of solvent Relative lowering of V.. = mole fraction of solute Relative lowering of vapour pressure is proportional to the mole fraction of solute. Explanation Definition. Q. No. 45 Assertion : The vapour pressure of a liquid decreases if some nonvolatile solute is dissolved in it. Reason : The relative lowering of vapour pressure of a solution containing a nonvolatile solute is equal to the mole fraction of the solute in the solution. If both Assertion & Reason are true and the reason is the correct explanation of the assertion If both Assertion & Reason but true and the reason is not the correct explanation of the assertion If assertion is true statement but Reason is false If both Assertion and Reason are false statement Explanation If both Assertion & Reason but true and the reason is not the correct explanation of the assertion Q. No. 46 Elevation in boiling point was C when 6 gm of a compound X was dissolved in 100

12 gm of water. Molecular weight of X is (K b of water is 0.52 K-kg/mol) Explanation = 0.52 M 0.1 M = 60 Q. No. 47 The molal b.p. constant for water is C kg mol -1. When 0.1 mole of sugar is dissolved in 200 g of water, the solution boils under a pressure of 1 atom at C kg/mol C kg/mol C kg/mol C kg/mol Explanation 0.1 T b = = T b = C kg/mol Q. No. 48 The latent heat of vaporization of water is 9700 cal/mole and if the b.p. is C, the ebullioscopic constant of water is C kg/mol C kg/mol C kg/mol C kg/mol Explanation 2 RTb Hvap using Kb = L vap = 1000L M H O vap 2 = C kg/mol Q. No. 49 The normal boiling point of toluene is C, and its boiling point elevation constant is 3.32 K kg mole -1. The enthalpy of vaporization of toluene is nearly 17.0 kj mol kj mol kj mol kj mol -1 Explanation 2 2 RTb RTb K b = L vap = 1000 Lvap 1000 kb L vap = 34.0 kj/mol Q. No. 50 The freezing point of a 0.05 molal solution of a non-electrolyte in water is C C C

13 C Explanation T = = b C freezing point = C Q. No. 51 During depression of freezing point in a solution the following are in equilibrium Liquid solution, solid solvent Liquid solvent, solid solute Liquid solute, solid solute Liquid solute, solid solvent Explanation Liquid solution, solid solvent Q. No. 52 Calculate the molecular weight of a substance if the freezing point of a solution containing 100 g of benzene and 0.2 g of a substance is 0.17 K below that of benzene. The cryoscopic constant of benzene is 5.16 K kg mol Explanation 0.2/M 0.17 = = Q. No. 53 On freezing an aqueous solution sugar, the solid that start separating out is Sugar Ice Solution with the same composition Solution with a different composition. Explanation Ice Q. No. 54 In the depression in freezing point experiment, it is observed that The vapour pressure of the solution is less than that of pure solvent. The vapour pressure of the solution is more than the of pure solvent Only solute molecules solidify at the freezing point Only solvent molecules solidify at the freezing point. Explanation Q. No. 55 Assertion: If more and more non-volatile solute is added to a solvent, the freezing point of the solution keeps on reducing. Reason : resence of large amount of the solid solute does not allow the solution to freeze. If both assertion & reason are true and the reason is the correct explanation of the assertion. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion. If Assertion is true statement but Reason is false.

14 If both Assertion and Reason are false statement. Explanation The reason is not the correct explanation of the assertion. Q. No. 56 When 1.0 of urea is dissolved in 200 g of an unknown solvent X, the X freezing point is lowered by C. When 1.5 g of an unknown, non-electrolytic solute Y is dissolved in 125 g of same solvent X, freezing point is lowered by C and vapour pressure is lowered by 1 %. If freezing point of X, is 12 0 C, determine molar enthalpy of fusion of X in kj. Correct Answer 0034 Is Integer Type Explanation = kj Q. No g of glucose 1, 10 g of urea 3 are dissolved in 250 ml of water at 300 K( = osmotic pressure of solution). The relationship between the osmotic pressure of the solution is 1 > 2 > 3 3 > 1 > 2 2 > 1 > 3 2 > 3 > 1 Explanation = > 180 = > 342 = = 2 > 1 > and 10 g of sucrose Q. No. 58 A semipermeable membrane Allows both the solute and solvent molecules to pass through Does not allow the solute and solvent molecules to pass through Allows only the solute molecules to pass through Allows the solvent molecules to pass through but blocks the passage of the solute molecules Explanation Allows the solvent molecules to pass through but blocks the passage of the solute molecules Q. No. 59 Which statement is incorrect about osmotic pressure, volume (V) and temperature (T)? 1 when T is constant. v T when V is constant. V when T is constant. V is constant when T is constant. Explanation V when T is constant.

15 Q. No. 60 The osmotic pressure of a solution increases if the Number of solute molecules is increased Temperature is decreased Volume is increased Value of R is increased Explanation = CRT Q. No. 61 Which of the following pairs of solution is isotonic? 6 % urea and 6 % glucose(w/v) 18 % urea and 18 % glucose (w/v) 6 % urea and 18 % fructose (w/v) 34.2 % sucrose and 60 % glucose(w/v) Explanation 6 18 = C urea C fructose = Q. No. 62 Two solutions A and B are separated by a semipermeable membrane. As a result of osmosis, the level of solution A is found to rise. It implies that Solution A is more concentrated than solution B Solution B is more concentrated than solution A The solute molecules of A are smaller than those of B The solute molecules of B are smaller than those of A. Explanation Fluid flows from lower to higher. Q. No. 63 Two aqueous solutions S 1 and S 2 are separated by a semi-permeable membrane. S 2 has lower vapour pressure than S 1. Then More solvent will flow from S 1 to S 2 More solvent will flow from S 2 to S 1 Solvent from S 1 and S 2 will flow at equal rates No flow will take place. Explanation Conceptual. Q. No. 64 What would happen if a thin slice of sugar beet is placed in a concentrated solution of NaCl? Sugar beet will lose water from its cells Sugar beet will absorb water from solution Sugar beet will neither absorb nor lose water Sugar beet will dissolve in solution Explanation Sugar beet will lose water from its cells Q. No. 65 A plant cell shrinks when it is kept in Hypotonic solution A hypertonic solution A solution isotonic with cell sap Water

16 Explanation A hypertonic solution Q. No. 66 Study the figure given aside and pick out the correct option(s) of the following: A white precipitate of AgCl is formed on AgNO 3 side A white precipitate of AgCl is formed on BaCl 2 side No precipitate is formed on either side Meniscus of BaCl 2 solution rises and that of AgNO 3 solution falls in due course of time Explanation No precipitate is formed on either side. Meniscus of BaCl 2 solution rises and that of AgNO 3 solution falls in due course of time Q. No. 67 Consider the following statements 1. Isotonic solutions has the same molar concentration at a given temperature. 2. The molal elevation constant K b is characteristic of a solvent, and is independent of the solute added. 3. The freezing point of a 0.1 M aqueous KCl solution is more than that of a 0.1 m aqueous AICI 3 solution. Which of these statements is correct. 1 and 2 2 and 3 1 and 3 1, 2 and 3 Explanation All three are correct. Q. No. 68 Raoult s law states that for a dilute solution, The lowering of vapour pressure is equal to the mole fraction of the solute The relative lowering of vapour pressure is proportional to the amount of solute in the solution The relative lowering of vapour pressure is equal to mole fraction of the solute The vapour pressure of the solution is equal to the mole fraction of the solvent Explanation The relative lowering of vapour pressure is equal to mole fraction of the solute Q. No. 69 Which one the following is not a colligative property? Relative lowering of vapour pressure of a solution Elevation in boiling point of a solution Critical point Osmotic pressure

17 Explanation Critical point. Others are colligative properties. Q. No. 70 Given that T f is the depression in freezing point of the solvent in a solution of a Tf nonvolatile solute of molality 1, the quantity It m is equal to m 1 L f (latent heat of fusion) K b (ebullioscopic constant) K f (cryoscopic constant) H fus (enthalpy of fusion) Explanation T f = K f m Tf It = Kf m1 m Q. No. 71 An aqueous solution freezes at C. What is its boiling point C C C C Explanation C H O H O b f K 2 = 0.52K/m; K 2 = 1.86K/m? Q. No. 72 Which of the following colligative properties can provide molar mass of proteins (or polymers of colloids) with greater precision? Relative lowering to vapour pressure Elevation of boiling point Depression is freezing point Osmotic pressure Explanation Osmotic pressure Q. No. 73 Colligative properties of a solution are Independent of the nature of solute Inversely proportional to molecular mass of solute roportional to concentration of solute Independent of the amount of solvent. Explanation Colligative properties of a solution are independent of the nature of solute, inversely proportional to molecular mass of solute, proportional to concentration of solute. Q. No. 74 H f = Molar heat of fusion of ice; L f = Latent heat of fusion of ice (g -1 ) H v = Molar heat of vaporization of water; L v = Latent heat of vaporization of water (g -1 ) Match the following appropriately No. Column A Column B Column C Id of Additional Answer

18 1 (A) Molal R (R) depression 1000 H f Containing 9.0 g of glucose in 50 g of water. 2 (B) Molal elevation R () 1000 H v Constant of water. 3 (C) T f of solution R (R) 1000 H f Containing 9.0 g of glucose in 50 g of water. 4 (D) T b of solution R () 1000 H v Constant of water. Explanation R Tb 2 Hvop K b = L vop = 1000 L MB vop R Tf 2 Hf K f = L f = 1000 L MB f R (S) 1000L f Containing 3.0 g of urea in 50 g of water R (Q) 1000L R (S) 1000L f Containing 3.0 g of urea in 50 g of water R (Q) 1000L v Constant of water. v Q. No. 75 If a solute undergoes dimerization and trimerization, the minimum values of the van t Hoff factors are 0.50 and and and and 0.67 Explanation 1 1 and 2 3 Q. No. 76 The van t Hoff factors i for an electrolyte which undergoes dissociation and association in solvents are respectively Greater than 1 and greater than 1 Less than 1 and greater than 1 Less than 1 and less than 1 Greater than 1 and less than 1 Explanation Greater than 1 and less than 1 Q. No. 77 When g to CuCl 2 is dissolved in 1 kg of water, the elevation in boiling point will be (K b = 0.52, molar mass of CuCl 2 = 134.5) Explanation Cucl 2 cu + 2cI Van t hoff factors is 3

19 T b = = Q. No. 78 Which one has the highest b.p? 0.1 N Na 2 SO N MgSO M Al 2 (SO 4 ) M BaSO 4 Explanation Al SO 2Al + 3SO = 0.1 M Al2(SO 4 ) 3 Q. No. 79 Which of the following aqueous solutions has the highest boiling point? 0.1 M KNO M Na 3 O M bacl M K 2 SO 4 Explanation Na3 O 4 3 Na + O 4 Q. No. 80 The freezing point of 1 molal NaCl solution assuming NaCl to be 100 % dissociated in water is C C C C Explanation 0 T = = C f Q. No. 81 The molal freezing point constant for water is C/ mole. Therefore, the freezing point of 0.1 M NaCl solution in water is expected to be C C C C Explanation 0 T = = C f Q. No M solution each of urea, common salt and Na 2 SO 4 are taken, the ratio of depression on freezing point is 1 : 1 : 1 1 : 2 : 1 1 : 2 : 3 2 : 2 : 3 Explanation Van t hoff factors Urea = 1, common salt = 2

20 Na2SO 4 3 = 1 : 2 : 3 Q. No. 83 The osmotic pressures of equimolar solution of Al 2 (SO 4 ) 3, KCl and sugar will be in the order KCl < Al SO < sugar 2 43 sugar < KCl < Al SO sugar > KCl > Al SO KCl < sugar < Al SO Explanation sugar < KCl < Al SO Q. No. 84 Solutions A, B, C and D are respectively 0.1 M glucose, 0.05 M NaCl, 0.05 M BaCl 2 and 0.1 M AlCl 3. Which of the following pairs is isotonic? A and B B and C A and D A and C Explanation for glucose for NaCl for BaCl for AlCl 3 Q. No M Na 2 SO 4 is isotonic with 0.01 M glucose. The degree of dissociation of Na 2 SO 4 is 75% 50% 25% 85% Explanation 0.01 = i i = = 75% 3-1 Q. No. 86 The average osmotic pressure of human blood is 7.8 bar at 37 0 C. What is the concentration of an aqueous NaCl solution that could be introduced in the bloodstream? 0.16 mol L mol L mol L mol L -1 Explanation = i CRT 7.8 = 2 C C = 0.16 mol/l -1

21 Q. No. 87 An aqueous solution of NaCl freezes at C. Given that K HO 2 b = K kg mol -1 and K HO 2 f = 1.86 K kg mole-1, the elevation in boiling point of this solution is K K K K Explanation = m T = = K b Q. No. 88 Among 0.1 M solutions of urea, Na 3 O 4 and Al 2 (SO 4 ) 3, which is incorrect The vapour pressure and freezing point are the lowest for urea The vapour pressure and freezing point are the highest for urea The boiling point is the highest for Al 2 (SO 4 ) 3 The depression in freezing point is the highest for Al 2 (SO 4 ) 3 Explanation Reason is due to Van t in off factors. Q. No. 89 Assertion : The boiling point of 0.1 M urea solution is less than of 0.1 M KCl solution. Reason : Elevation of boiling point is directly proportional to the number of species present in the solution. If both assertion & reason are true and the reason is the correct explanation of the assertion If both Assertion & Reason are true but the reason is not the correct explanation of the assertion If Assertion is true statement but Reason is false If both Assertion and Reason are false statement Explanation If both assertion & reason are true and the reason is the correct explanation of the assertion Q. No. 90 Assertion : NaCl in water and organic acids in benzene show abnormal molecule mass. Reason : Abnormal molecular mass is obtained when the substance in the solution undergoes dissociation or association. If both assertion & reason are true and the reason is the correct explanation of the assertion If both Assertion & Reason are true but the reason is not the correct explanation of the assertion If Assertion is true statement but Reason is false If both Assertion and Reason are false statement Explanation If both assertion & reason are true and the reason is the correct explanation of the assertion assage Text A protein has been isolated as sodium salt with their molecular formula Na x (this notation means xna + ions are associated with a negatively charged protein -x ). A solution of this salt was prepared by dissolving 0.25 g of this sodium salt of protein in 10 g of water and

22 -3 ebullioscopic analysis revealed that solution boils at temperature C higher than the normal boiling point of pure water. Kb of water of 0.52 K kg mol -1. Also elemental analysis revealed that the salt contain 1% sodium metal by weight. Q. No. 91 Deduce molecular formula of protein. Na Na 2 Na 4 Na 5 Explanation = x + 1 M x = M M x Nax xna + x + 1 = i 23 x 100 = 1% M x 1 = M = M M = Na 5 Q. No. 92 Determine molecular weight of sodium salt of protein Explanation 23 x M 100 = 1% x 1 = M = M M = Q. No. 93 Determine molecular weight of acidic from of protein: Explanation Q. No. 94 M n = Normal molecular mass of solute M o = Observed molecular mass of solute from colligative property measurement No. Column A Column B Column C Id of Additional Answer

23 1 (A) M o < Mn (R) 0.05 M barium chloride in water. 2 M (B) n (R) 0.05 M barium M o 3 chloride in water. 3 (C) M o > Mn () 0.1 M CH 3 COOH is benzene. 4 (D) M o = M n (Q) 0.05 M barium chloride in water. Explanation Based on Van t hoff vactors. (S) 0.1 M CH 3 COOH in water. Q. No. 95 A mixture of NaCl sucrose of combined mass 10.2 g is dissolved in enough water to make up a250 ml solution. The osmotic pressure of the solution is 7.32 atm at 23 0 C. Calculate the mass percentage of NaCl in the mixture. Correct Answer (0020) Is Integer Type Explanation x y of NaCl ( x) g of sucrose x 7.32 = Q. No. 96 A non-volatile organic compound X was used to makeup two solutions. Solution A contains 5.0 g of X in 100 g of water and solution B contains 2.0 g of X in 100 g of benzene. Solution A has vapour pressure of mm of Hg at normal boiling point of water and solution B has the same vapour pressure at the normal boiling point of benzene. Assuming X undergo partial dimerization in benzene, determine percentage of X dimerized in benzene solution. Correct Answer 0085 Is Integer Type Explanation 5 18 i 2 78 = M 100 M 100 i % = = % = 85