Tiêu đề 2. SOLUTIONS - Questions.pdf ✅

2. SOLUTIONS (1.)The empirical formula of a nonelectrolyte is CH2O. A solution containing 3 g of the compound exerts the same osmotic pressure as that of 0.05 M glucose solution. The molecular formula of the compound is (a.) CH2O (b.) C2H4O2 (c.) C4H8O4 (d.) C3H6O3 (2.)The freezing point of water is depressed by 0.37°C in a 0.01 mol NaCl solution. The freezing point of 0.02 molal solution of urea is depressed by (a.) 0.37°C (b.) 0.74°C (c.) 0.185°C (d.) 0°C (3.)If α is the degree of dissociation of Na2SO4 the van’t Hoff factor (i) used for calculating the molecular mass is (a.) 1 − 2 α (b. ) 1 + 2 α (c.) 1 − α (d. ) 1 + α (4.)The normality of 10% (weight/volume) acetic acid is (a.) 1 N (b.) 1.3 N (c.) 1.7 N (d.) 1.9 N (5.)Osmatic pressure is 0.0821 atm at temperature of 300 K. Find concentration in mole per litre (a.) 0.33 (b.) 0.22 × 10−2 (c.) 0.33 × 10−2 (d.) 0.44 × 10−2 (6.)Molecular weight of glucose is 180. A solution of glucose which contains 18 g/L, is (a.) 0.1 molal (b.) 0.2 molal (c.) 0.3 molal (d.) 0.4 molal (7.)The Henry’s law constant for the solubility of N2 gas in water at 298 K is 1.0 × 105 atm. The mole fraction of N2 In air is 0.8 The number of moles of N2 from air dissolved in 10 moles of water of 298 K and 5 atm pressure is (a.) 4 × 10−4 (b.) 4.0 × 10−5 (c.) 5.0 × 10−4 (d.) 4.0 × 10−6 (8.)At80∘C , the vapour pressure of pure liquid ‘A’ is 520 mm Hg and that of pure liquid ‘B’ is 1000 mm Hg. If a mixture solution of ‘A’ and ‘B’ boils at 80∘C and 1 atm pressure, the amount of ‘A’ in the mixture is (1 atm = 760 mm Hg) (a.) 52 mole per cent (b.) 34 mole per cent (c.) 48 mole per cent (d.) 50 mole per cent (9.)Which has the minimum freezing point? (a.) One molal NaCl aqueous solution (b.) One molal CaCl2 aqueous solution (c.) One molal KCl aqueous solution (d.) One molal urea aqueous solution (10.)If liquids A and B form an ideal solution, the (a.) Enthalpy of mixing is zero (b.) Entropy of mixing is zero (c.) Free energy of mixing is zero (d.) Free energy as well as the entropy of mixing are each zero (11.)The vapour pressure of benzene at a certain temperature is 640 mm of Hg. A non-volatile and non-electrolyte solid weighing 2.175 g is added to 39.08 g of benzene. If the vapour pressure of the solution is 600 mm of Hg, what is the molecular weight of solid substance? (a.) 49.50 (b.) 59.60 (c.) 69.60 (d.) 79.82 (12.)The normality of a 100 mL solution of sodium hydroxide which contains 4 g of NaOH, is (a.) 0.5 (b.) 1.0 (c.) 1.5 (d.) 2.0 (13.)The freezing point (in°C) of solution containing 0.1 g of K3 [Fe(CN)6 ](mol.wt 329) in 100 g of water (Kf = 1.86 K kg mol −1 )is (a.) −2.3 × 10 −2 (b.) −5.7 × 10 −2 (c.) −5.7 × 10 −3 (d.) −1.2 × 10 −2 (14.)The freezing point depression of 0.001 m, Kx [Fe(CN)6 ]is 7.10 × 10−3K. If for water, kf is 1.86 K Kg mol −1 , value of x will be (a.) 4 (b.) 3 (c.) 2
(d.) 1 (15.)The freezing point of one modal NaCl solution assuming NaCl to be 100 % dissociated in water is (modal depression constant=1.86) (a.) −2.72°C (b.) −3.72°C (c.) 2.72°C (d.) 3.72°C (16.)What is the total number of moles of H2SO4 needed to prepare 5.0 L of a 2.0 M solution of H2SO4 ? (a.) 2.5 (b.) 5.0 (c.) 10 (d.) 20 (17.)35.4 mL of HCl is required for the neutralisation of a solution containing 0.275 g of sodium hydroxide. The normality of hydrochloric acid is (a.) 0.97 N (b.) 0.142 N (c.) 0.194 N (d.) 0.244 N (18.)How much K2Cr2O7 (Mol. wt. = 294.19) is required to prepare one litre of 0.1 N solution? (a.) 9.8063 g (b.) 7.3548 g (c.) 3.6774 g (d.) 4.903 g (19.)Which of the following is a colligative property? (a.) Boiling point (b.) Freezing point (c.) Osmotic pressure (d.) Vapour pressure (20.)A mixture of ethyl alcohol and propyl alcohol has a vapour pressure of 290 mm at 300 K. the vapour pressure of propyl alcohol is 200 mm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure (in mm) at the same temperature will be (a.) 350 (b.) 300 (c.) 700 (d.) 360 (21.)A 5% solution of cane sugar (molar mass 342) is isotonic with 1% of a solution of an unknown solute. The molar mass of unknown solute in g/mol is (a.) 136.2 (b.) 171.2 (c.) 68.4 (d.) 34.2 (22.)The vapour pressure of a pure liquid A is 40 mm Hg at 310 K. The vapour pressure of this liquid in a solution with liquid B is 32 mm Hg. What is the mole fraction of A in the solution if it obeys the Raoult’s law? (a.) 0.5 (b.) 0.6 (c.) 0.7 (d.) 0.8 (23.)At a constant temperature, which of the following aqueous solutions will have the maximum vapour pressure? (Mol. wt NaCl =58.5, H2SO4 = 98.0 g. mol −1 ) (a.) 1 molal NaCl (aq) (b.) 1 molar NaCl (aq) (c.) 1 molal H2SO4 (aq) (d.) 1 molar H2SO4 (aq) (24.)If 117 g NaCl is dissolved in 1000 g of water the concentration of the solution is said to be (a.) 2 molar (b.) 2 molal (c.) 1 normal (d.) 1 molal (25.)The ionic strength of solution containing 0.1 mol/kg of KCl and 0.2 mol/kg of Cu SO4 is (a.) 0.3 (b.) 0.6 (c.) 0.9 (d.) 0.2 (26.)What is the freezing point of a solution containing 8.1 g HBr in 100 g water assuming the acid to be 90% ionised? (kffor wt. = 1.86 K mol −1 ) (a.) 0.85 ∘C (b.) −3.53 ∘C (c.) 0 ∘C (d.) −0.35 ∘C (27.)A solution of 4.5 g of a pure non-electrolyte in 100 g of water was found to freeze at 0.465°C . The molecular weight of the solute closest to (kf = 1.86) (a.) 135.0 (b.) 172.0 (c.) 90.0 (d.) 180.0 (28.)The vapour pressure of water at 20°C is 17.54 mm. When 20 g of a non-ionic, substance is dissolved in 100 g of water, the vapour pressure is lowered by 0.30 mm. What is the molecular mass of the substance? (a.) 200.8 (b.) 206.88 (c.) 210.5 (d.) 215.2 (29.)Formation of a solution from two components can be considered as
(1) pure solvent → separated solvent molecules, ∆H1 (2) pure solute → separated solvent molecules, ∆H2 (3) separated solvent and solute molecules → solution, ∆H3 Solution so formed will be ideal if (a.) ∆Hsoln = ∆H1 − ∆H2 − ∆H3 (b.) ∆Hsoln = ∆H3 − ∆H1 − ∆H2 (c.) ∆Hsoln = ∆H1 + ∆H2 + ∆H3 (d.) ∆Hsoln = ∆H1 + ∆H2 − ∆H3 (30.)When WB g solute (molecular mass MB) dissolves in WA g solvent, the molality M of the solution is (a.) WB MB × 1000 WA (b.) WA MB × 1000 WB (c.) WB WA × MA 1000 (d.) WA WB × MB 1000 (31.)Dissolving 120 g of urea (mol. Wt. 60) in1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is (a.) 1.78M (b.) 2.00M (c.) 2.05M (d.) 2.22M (32.)The osmotic pressure of 0.2 molar solution of urea at 27°C (R=0.082 L atm mol −1K −1 )is (a.) 4.92 atm (b.) 1 atm (c.) 0.2 atm (d.) 27 atm (33.)19.85 mL of 0.1 N NaOH reacts with 20 mL of HCl solution for complete neutralization. The molarity of HCl solution is (a.) 9.9 (b.) 0.99 (c.) 0.099 (d.) 0.0099 (34.)What is the molarity of 0.2 N Na2CO3solution? (a.) 0.1 M (b.) 0 M (c.) 0.4 M (d.) 0.2 M (35.)The vapour pressure of water at 23°C is 19.8 mm. 0.1 mole of glucose is dissolved in 178.2 g of water. What is the vapour pressure (in mm) of the resultant solution? (a.) 19.0 (b.) 19.602 (c.) 19.402 (d.) 19.202 (36.)The molarity of a solution made by mixing 50 mL of conc H2SO4 (36 N) with 50 mL of water is (a.) 9 m (b.) 10 m (c.) 11 m (d.) 12 m (37.)What is the freezing point of a solution containing 8.1 g HBr in 100 g water assuming the acid to be 90% ionised? (kf for water = 1.86 K mol −1 ) (a.) 0.85°C (b.) -3.53°C (c.) 0°C (d.) -0.35°C (38.)How many moles of Al2 (SO4 )3 would be in 50 g of the substance? (a.) 0.083 mol (b.) 0.952 mol (c.) 0.481 mol (d.) 0.140 mol (39.)In which ratio of volume 0.4 M HCl and 0.9 M HCl are to be mixed such that the concentration of the resultant solution becomes 0.7 M ? (a.) 4 : 9 (b.) 2 : 3 (c.) 3 : 2 (d.) 1 : 1 (40.)A binary liquid solution ois prepared by mixing n-heptane and ethanol. Which one of the following statements is correct regarding the behaviour of the solution? (a.) The solution formed is an ideal solution (b.) The solution is non-ideal, showing positive deviation from Raoult’s law (c.) The solution is non-ideal, showing negative deviation from Raoult’s law (d.) n-heptane shows positive deviation while ethanol show negative deviation from Raoult’s law (41.)An aqueous solution of 6.3 g oxalic acid dihydrate is made up to 250 mL. The volume of 0.1 N sodium hydroxide required to completely neutralise 10 mL of this solution is (a.) 40 mL (b.) 20 mL (c.) 10 mL (d.) 4 mL (42.)Van’t hoff factor of Ca(NO3)2 is (a.) One (b.) Two (c.) Three (d.) four (43.)The average osmotic pressure of human blood is 7.8 bar at 37°C. What is the concentration of an
aqueous NaCl solution that could be used in the blood steam? (a.) 0.16 mol/L (b.) 0.31 mol/L (c.) 0.60 mol/L (d.) 0.45 mol/L (44.)The statement “the relative lowering of the vapour pressure is equal to th ratio ot moles of the solute to the total number of the moles in the solution” refers to (a.) Decrease the freezing point of water in the winter and increase the boiling point of water in the summer (b.) Only decrease the freezing point of water (c.) Only increase the boiling point of water (d.) Be used for cleaning the radiator in a car (45.)A 5 molar solution of H2 SO4 is diluted from 1 L to 10 L. What is the normality of the solution? (a.) 0.25 N (b.) 1 N (c.) 2 N (d.) 7 N (46.)The increase in boiling point of a solution containing 0.6 g urea in 200 g water is 0.50∘C.Find the molal elevation constant. (a.) 10 K kg mol −1 (b.) 10 K g mol −1 (c.) 10 K kg mol (d.) 1.0 K kg mol −1 (47.)2.5 L of NaCl solution contain 5 moles of the solute.What is the molarity ? (a.) 5M (b.) 2M (c.) 2.5M (d.) 12.5M (48.)Calculate the normality of 250 mL aqueous solution of H2SO4 having pH = 0.00. (a.) 0.25 N (b.) 0.50 N (c.) 1 N (d.) 2 N (49.)The degree of dissociation (α) of a weak electrolyte , AxBy is related to van’t Hoff factor (i) by the expression (a.) α = i−1 (x+y−1) (b.) α = i−1 x+y+1 (c.) α = x+y−1 i−1 (d.) α = x+y+1 i−1 (50.)If 0.15 g of a solute, dissolved in 15 g of solvent, is boiled at a temperature higher by 0.216°C than that of the pure solvent. The molecular weight of the substance (molal elevation constant for the solvent is 2.16°C) is (a.) 100 (b.) 10.1 (c.) 10 (d.) 1.001 (51.)Osmotic pressure of 0.4% urea solution is 1.60 atm and that of 3.42% cane sugar is 2.46 atm. When the above two solutions are mixed, the osmotic pressure of the resulting solution is (a.) 0.82 atm (b.) 2.46 atm (c.) 1.64 atm (d.) 4.10 atm (52.)Volume of 0.6 M NaOH required to neutralise 30 cm3 of 0.4 M HCl is (a.) 20 cm3 (b.) 40 cm3 (c.) 45 cm3 (d.) 30 cm3 (53.)Which of the following concentration term is/are independent of temperature? (a.) Molarity (b.) Molarity and mole fraction (c.) Mole fraction and molality (d.) Molality and normality (54.)How much of 0.1 M H2 SO4 solution is required to neutralise 50 mL of 0.2 M NaOH solution? (a.) 50 mL (b.) 5.0 mL (c.) 0.50 mL (d.) 100 mL (55.)For an aqueous solution, freezing point is −0.186°C. Elevation of the boiling point of the same solution is (kf = 1.86° mol −1 kg and kb = 0.512° mol −1 kg) (a.) 0.186° (b.) 0.0512° (c.) 1.86° (d. ) 5.12° (56.)40% by weight solution will contain how much mass of the solute in 1L solution, density of the solution is 1.2 g/mL? (a.) 480 g (b.) 48 g (c.) 38 g (d.) 380 g (57.)Phenol dimerises in benzene having van’t Hoff factor 0.54. What is the degree of association? (a.) 1.92 (b.) 0.98 (c.) 1.08 (d.) 0.92