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Solutions Class 12 Chemistry MCQ Questions with Answers
Refer below for MCQ Class 12 Chemistry Chapter 2 Solutions with solutions. Solve questions and compare with the answers provided below
Question. Vapour pressure of benzene at 30°C is 121.8 mm Hg. When 15 g of a non volatile solute is dissolved in 250 g of benzene its vapour pressure decreased to 120.2 mm Hg. The molecular weight of the solute (Mo. wt. of solvent = 78)
Question. We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1M, 0.01M and 0.001M, respectively. The value of van’t Hoff factor for these solutions will be in the order ________.
(a) iA < iB < iC
(b) iA > iB > iC
(c) iA = iB = iC
(d) iA < iB > iC
Question.The value of P° for benzene is 640 mm of Hg. The vapour pressure of solution containing 2.5gm substance in 39gm. benzene is 600mm of Hg the molecular mass of X is
Question. The freezing point of equimolal aqueous solutions will be highest for
(a) C6H5NH3 +Cl– (aniline hydrochloride)
(d) C6H12O6 (glucose)
Question. Which one of the following is non-ideal solution
(a) Benzene + toluene
(b) n-hexane + n-heptane
(c) Ethyl bromide + ethyl iodide
(d) CCl4 + CHCl3
Question. Which one of the following is a colligative property ?
(a) Boiling point
(b) Vapour pressure
(c) Osmotic pressure
(d) Freezing point
Question. The correct relationship between the boiling points of very dilute solutions of AlCl3 (t1) and CaCl2 (t2), having the same molar concentration is
(a) t1 = t2
(b) t1 > t2
(c) t2 > t1
(d) t2 ≥ t1
Question. The vapour pressure of water at 20°C is 17.5 mm Hg. If 18 g of glucose (C6H12O6) is added to 178.2 g of water at 20°C, the vapour pressure of the resulting solution will be
(a) 17.325 mm Hg
(b) 15.750 mm Hg
(c) 16.500 mm Hg
(d) 17.500 mm Hg
Question. The vapour pressure of two liquids X and Y are 80 and 60 torr respectively. The total vapour pressure of the ideal solution obtained by mixing 3 moles of X and 2 moles of Y would be
(a) 68 Torr
(b) 140 Torr
(c) 48 Torr
(d) 72 Torr
Question. The rise in the boiling point of a solution containing 1.8 g of glucose in 100 g of solvent is 0.1°C. The molal elevation constant of the liquid is
(a) 0.01 K/m
(b) 0.1 K/m
(c) 1 K/m
(d) 10 K/m
Question. 1.00 g of a non-electrolyte solute (molar mass 250 g mol–1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, Kf of benzene is 5.12 K kg mol–1, the freezing point of benzene will be lowered by
(a) 0.3 K
(b) 0.5 K
(c) 0.4 K
Question. A 0.5 molal solution of ethylene glycol in water is used as coolant in a car. If the freezing point constant of water be 1.86°C per mole, the mixture shall freeze at
Question. A solution of urea (mol. mass 56 g mol-1) boils at 100.180C at the atmospheric pressure. If Kf and Kb for water are 1.86 and 0.512 K kg mol-1 respectively, the above solution will freeze at
(b) – 0.654°C
Question. The freezing point of 1% solution of lead nitrate in water will be
(d) below 0°C
Question. Most of the processes in our body occur in
(a) solid solution
(b) liquid solution
(c) gaseous solution
(d) colloidal solution
Question. A solution of sucrose (molar mass = 342 g mol–1) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water.The freezing point of the solution obtained will be
(Kf for water = 1.86 K kg mol–1).
(a) – 0.372°C
(b) – 0.520°C
(d) + 0.372°C
(d) – 0.570°C
Question. Which is an application of Henry’s law?
(a) Spray paint
(b) Bottled water
(c) Filling up atire
(d) Soft drinks (soda)
Question. A solution containing 1.8 g of a compound (empirical formula CH2O) in 40 g of water is observed to freeze at –0.465° C.The molecular formula of the compound is (Kf of water = 1.86 kg K mol–1)
Question. Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon __________.
(b) Nature of solute
(d) Nature of solvent
Question. 12 g of a nonvolatile solute dissolved in 108 g of water produces the relative lowering of vapour pressure of 0.1.The molecular mass of the solute is
Question. Low concentration of oxygen in the blood and tissues of people living at high altitude is due to _________.
(a) low temperature
(b) low atmospheric pressure
(c) high atmospheric pressure
(d) both low temperature and high atmospheric pressure
Question. As a result of osmosis, the volume of more concentrated solution
(a) gradually decreases
(b) gradually increases
(c) is not affected
(d) suddenly increases
Question. Osmotic pressure of a solution at a given temperature
(a) increases with concentration
(b) decreases with concentration
(c) remains same
(d) initially increases and then decreases
Question. At 25°C, at 5 % aqueous solution of glucose (molecular weight = 180 g mol–1) is isotonic with a 2% aqueous solution containing an unknown solute. What is the molecular weight of the unknown solute?
Question. Which one of the following statements is false?
(a) Raoult’s law states that the vapour pressure of a component over a binary solution of volatile liquids is directly proportional to its mole fraction
(b) Two sucrose solutions of the same molality prepared in different solvents will have the same depression of freezing point
(c) The correct order of osmotic pressures of 0.01 M solution of each compound is BaCl2 > KCl > CH3COOH > glucose
(d) In the equation osmotic pressureπ = MRT, M is the molarity of the solution
Question. Which of the following statements is false?
(a) Units of atmospheric pressure and osmotic pressure are the same.
(b) In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
(c) The value of molal depression constant depends on nature of solvent.
(d) Relative lowering of vapour pressure, is a dimensionless quantity.
Question. Which of the following concentration unit is independent of temperature ?
Question. If 0.1 M solution of glucose and 0.1 M solution of urea are placed on two sides of the semipermeable membrane to equal heights, then it will be correct to say that
(a) there will be no net movement across the membrane
(b) glucose will flow towards urea solution
(c) urea will flow towards glucose solution
(d) water will flow from urea solution to glucose
Question. The van’t Hoff factor i for a compound which undergoes dissociation in one solvent and association in other solvent is respectively
(a) less than one and greater than one.
(b) less than one and less than one.
(c) greater than one and less than one.
(d) greater than one and greater than one.
Question. If the various terms in the given below expressions have usual meanings, the van’t Hoff factor (i) cannot be calculated by which one of the following expressions
Question. Van’t Hoff factor is given by the expression ________.
(a) i= Normalmolar mass/Abnormal molar mass
(b) i= Abnormal molar mass/Normalmolar mass
(c) i= Observed colligativeproperty/Calculated colligativeproperty
(d) Both (a) and (c)
Question. Negative deviation from Raoult’s law is observed in which one of the following binary liquid mixtures?
(a) Ethanol and acetone
(b) Benzene and toluene
(c) Acetone and chloroform
(d) Chloroethane and bromoethane
Question. If α is the degree of dissociation of Na2SO4, the Vant Hoff’s factor (i) used for calculating the molecular mass is
(a) 1 + α
(b) 1 – α
(c) 1 + 2α
(d) 1 – 2α
Question. At 25°C, the highest osmotic pressure is exhibited by 0.1 M solution of
Question. Which of the following factor do not affect solubility of solid solute in liquid ?
(c) Nature of solute
(d) All of these
Question. Which one of the following salts will have the same value of van’t Hoff factor (i) as that of K4[Fe(CN)6].
Question. The vapour pressure at a given temperature of an ideal solution containing 0.2 mol of a non-volatile solute and 0.8 mol of solvent is 60 mm of Hg. The vapour pressure of the pure solvent at the same temperature is
(a) 150 mm of Hg
(b) 60 mm of Hg
(c) 75 mm of Hg
(d) 120 mm of Hg
Question. Which of the following 0.10 m aqueous solutions will have the lowest freezing point ?
Question. During osmosis, flow of water through a semipermeable membrane is
(a) from both sides of semipermeable membrane with equal flow rates
(b) from both sides of semipermeable membrane with unequal flow rates
(c) from solution having lower concentration only
(d) from solution having higher concentration only
Question. For an electrolyte, elevation of B.P. is directly proportional to
(c) mole fraction
(d) All of these
Question. Which of the following is dependent on temperature?
(b) Mole fraction
(c) Weight percentage
Question. What is the mole fraction of the solute in a 1.00 m aqueous solution?
Question. How many grams of concentrated nitric acid solution should be used to prepare 250 mL of 2.0 M HNO3? The concentrated acid is 70% HNO3.
(a) 70.0 g conc. HNO3
(b) 54.0 g conc. HNO3
(c) 45.0 g conc. HNO3
(d) 90.0 g conc. HNO3
Question. Which of the following compounds can be used as antifreeze in automobile radiators?
(a) Methyl alcohol
(d) Ethyl alcohol
Question. Concentrated aqueous sulphuric acid is 98% H2SO4 by mass and has a density of 1.80 g mL–1. Volume of acid required to make one litre of 0.1 M H2SO4 solution is
(a) 16.65 mL
(b) 22.20 mL
(c) 5.55 mL
(d) 11.10 mL
Question. The mole fraction of the solute in one molal aqueous solution is
Question. 2.5 litre of 1 M NaOH solution is mixed with another 3 litre of 0.5 M NaOH solution. Then find out molarity of resultant solution.
(a) 0.80 M
(b) 1.0 M
(c) 0.73 M
(d) 0.50 M
Question. How many g of dibasic acid (mol. weight 200) should be present in 100 mL of the aqueous solution to give strength of 0.1 N?
(a) 10 g
(b) 2 g
(c) 1 g
(d) 20 g
Question. What is the molarity of H2SO4 solution, that has a density 1.84 g/cc at 35°C and contains 98% by weight?
(a) 18.4 M
(b) 18 M
(c) 4.18 M
(d) 8.14 M
Question. The concentration unit, independent of temperature, would be
(b) weight volume percent
Question. How many grams of CH3OH should be added to water to prepare 150 mL solution of 2 M CH3OH?
(a) 9.6 × 103
(b) 2.4 × 103
Question. In water saturated air, the mole fraction of water vapour is 0.02. If the total pressure of the saturated air is 1.2 atm, the partial pressure of dry air is
(a) 1.18 atm
(b) 1.76 atm
(c) 1.176 atm
(d) 0.98 atm.
Question. pA and pB are the vapour pressures of pure liquid components, A and B, respectively of an ideal binary solution. If xA represents the mole fraction of component A, the total pressure of the solution will be
(a) pA + xA(pB – pA)
(b) pA + xA ( pA – pB)
(c) pB + xA(pB – pA)
(d) pB + xA ( pA – pB)
Question. Vapour pressure of chloroform (CHCl3) and dichloromethane (CH2Cl2) at 25°C are 200 mm Hg and 41.5 mm Hg respectively. Vapour pressure of the solution obtained by mixing 25.5 g of CHCl3 and 40 g of CH2Cl2 at the same temperature will be (Molecular mass of CHCl3 = 119.5 u and molecular mass of CH2Cl2 = 85 u)
(a) 173.9 mm Hg
(b) 615.0 mm Hg
(c) 347.9 mm Hg
(d) 285.5 mm Hg
Question. A solution has a 1 : 4 mole ratio of pentane to hexane.
The vapour pressures of the pure hydrocarbons at 20 °C are 440 mm Hg for pentane and 120 mm Hg for hexane. The mole fraction of pentane in the vapour phase would be
Question. The vapour pressure of two liquids P and Q are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 mole of P and 2 mol of Q would be
(a) 72 torr
(b) 140 torr
(c) 68 torr
(d) 20 torr
Question. The mixture which shows positive deviation from Raoult’s law is
(a) ethanol + acetone
(b) benzene + toluene
(c) acetone + chloroform
(d) chloroethane + bromoethane.
Question. For an ideal solution, the correct option is
(a) DmixG = 0 at constant T and P
(b) DmixS = 0 at constant T and P
(c) Dmix V ≠ 0 at constant T and P
(d) Dmix H = 0 at constant T and P.
Question. The mixture that forms maximum boiling azeotrope is
(a) heptane + octane
(b) water + nitric acid
(c) ethanol + water
(d) acetone + carbon disulphide.
Question. Which of the following statements is correct regarding a solution of two components A and B exhibiting positive deviation from ideal behaviour?
(a) Intermolecular attractive forces between A-A and B-B are stronger than those between A-B.
(b) Δmix H = 0 at constant T and P.
(c) Δmix V = 0 at constant T and P.
(d) Intermolecular attractive forces between A-A and B-B are equal to those between A-B.
Question. Which one of the following is incorrect for ideal solution?
(a) DHmix = 0
(b) DUmix = 0
(c) DP = Pobs – Pcalculated by Raoult’s law = 0
(d) DGmix = 0
Question. Which of the following statements about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at 25°C.
(Given, vapour pressure data at 25°C, benzene = 12.8 kPa, toluene = 3.85 kPa)
(a) The vapour will contain equal amounts of benzene and toluene.
(b) Not enough information is given to make a prediction.
(c) The vapour will contain a higher percentage of benzene.
(d) The vapour will contain a higher percentage of toluene.
Question. The osmotic pressure of 0.2 molar solution ofw·ea at 27°C (R = 0.082L atrn mol-1 K-1) is
(a) 4.92 atm
(b) 1 atrn
(c) 0.2 atm
(d) 27 atrn
Question. Dry air is passed through a solution containing 10 g of a solute in 90 g of water and then through pure water. The loss in weight of solution is 2.5 g and that of pure solvent is 0.05 g. Calculate the molecular weight of the solute.
Question. Calculate the molal depression constant of a solvent which has freezing point 16.6°C and latent heat of fusion 180.75 Jg-1 ·
Question. In an osmotic pressure measurement experiment, a 5% solution of compound’ X’ is found to be isotonic with a 2% acetic acid solution. The gram molecular mass of X’ is
Question. By dissolving 5 g substance in 50 g of water, the decrease in freezing point is 1.2°C. The gram molal depression is 1.85°C. The molecular weight of substance is
Question. The volume of water to be added to 100cm3 of 0.5 N H2SO4 to get decinormal concentration is
Question. 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 ?
Question. van’t Hoff factor of Ca(NO3 )2 is
Question. van ‘t Hoff factor more than unity indicates that the solute in solution has
(c) Both (a) and (b)
(d) cannot say anything
Question. Abnormal colligative properties are observed only when the dissolved non-volatile solute in a given dilute solution
(a) is a non-electrolyte
(b) offers an intense colour
(c) associates or dissociates
(d) offers no colour
Question. Phenol dimerises in benzene having van’t Hoff factor 0.54. What is the degree of association ?
Question. Osmotic pressure observed when benzoic acid is dissolved in benzene is less than that expected from theoretical considerations. This is because
(a) benzoic acid is an organic solute
(b) benzoic acid bas higher molar mass than benzene
(c) benzoic acid gets associated in benzene
(d) benzoic acid gets dissociated in benzene
Question. When 20 g ofnaphthoic acid (C11H8O2 )is dissolved in 50 g of benzene ( Kf = 1.72 K kg mol-1 ), a freezing point depression of 2 ‘lis observed. The van’t Hoff factor (i) is
Question. Observe the following abbreviations πobs = observed colligative property, πcal = theoretical colligative property assuming normal behaviour of solute. van ‘t Hoff factor (i) is given by
(a) i = πobs X πcal
(b) i = πobs + πcal
(c) i = πobs – πcal
(d) i = πobs / πcal
Question. The elevation in boiling point of a solution of 13.44 g of CuCl2 in 1 kg of water using the following infom1ation will be (molecular weight of CuCl2 = 134. 4 and kb = 0.52Km-1)
Question. Distribution law was given by
(b) van’t Hoff
Question. Ifa is the degree of dissociation of Na2SO4 , the van ‘t Hoff factor (i) used for calculating the molecular mass is
(a) 1 – 2α
(b) 1 + 2α
(c) 1 – α
(d) 1 + α
Question. The van’t Hoff factor of BaCl2 at 0.01 M concentration is 1.98. The percentage of dissociation of BaCl2 at this concentration is
Question. One gram of silver gets distributed between 10 cm3 of molten zinc and 100 cm3 of molten lead at 800°C. The percentage of silver still left in the lead layer in approximately. Distributed coefficient = 300
Question. Which of the following is incorrect?
(a) Relative lowering of vapour pressure is independent of the nature of the solute and the solvent.
(b) The relative lowering of vapour pressure is a colligative property.
(c) Vapour pressure of a solution is lower than the vapour pressure of the sol vent.
(d) The relative lowering of vapour pressure is directly proportional to the original pressure.
Question. X is dissolved in water. Maximum boiling point is observed when X is … (0.1 M each)
Question. Which one of the following concentration units is independent of temperature ?
Question. Solution A contains 7 g/L of MgCl2 and solution B contains 7 g/L of NaCl. At room temperature, the osmotic pressure of
(a) solution A is greater than B
(b) both have same osmotic pressure
(c) solution B is greater than A
(d) cannot be determine
Question. At certain temperature a 5.12% solution of cane sugar is isotonic with a 0.9% solution of an unknown solute. The molar mass of solute is
Question. The density (in g mL-1) of a 3.60 M sulphuric acid solution that is 29% H2SO4 (molar mass = 98 g mol-1 ) by mass will be
Question. Which bas minimum osmotic pressure ?
(a) 200 mL of 2 M NaCl solution
(b) 200 mL of 1 M glucose solution
(c) 200 mL of 2 M urea solution
(d) All have same osmotic pressure
Question. The vapour pressure will be lowest for
(a) 0. 1 M sugar solution
(b) 0.1 M KCl solution
(c) 0. 1 M Cu(NO3 )2 solution
(d) 0.1 M AgNO3 solution
Question. Osmotic pressure of 0.4% urea solution is 1.64 atrn 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 atrn
(b) 2.46 atm
(c) 1.64 atm
(d) 4.10 atm
Question. Which condition is not satisfied by an ideal solution?
(a) DmixV = 0
(b) DmixS = 0
(c) Obeyance to Raoult’s Law
(d) DmixH = 0
Question. A solution of acetone in ethanol
(a) obeys Raoult’s law
(b) shows a negative deviation from Raoult’s law
(c) shows a positive deviation from Raoult’s law
(d) behaves like a near ideal solution.
Question. A solution containing components A and B follows Raoult’s law
(a) A – B attraction force is greater than A – A and B – B
(b) A – B attraction force is less than A – A and B – B
(c) A – B attraction force remains same as A – A and B – B
(d) volume of solution is different from sum of volume of solute and solvent.
Question. All form ideal solution except
(a) C6H6 and C6H5CH3
(b) C2H6 and C2H5I
(c) C6H5Cl and C6H5Br
(d) C2H5I and C2H5OH
Question. An ideal solution is formed when its components
(a) have no volume change on mixing
(b) have no enthalpy change on mixing
(c) have both the above characteristics
(d) have high solubility.
Question. The freezing point depression constant (Kf) of benzene is 5.12 K kg mol–1. The freezing point depression for the solution of molality 0.078 m containing a non-electrolyte solute in benzene is (rounded off upto two decimal places)
(a) 0.20 K
(b) 0.80 K
(c) 0.40 K
(d) 0.60 K
Question. If molality of the dilute solution is doubled, the value of molal depression constant (Kf) will be
Question. At 100°C the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If Kb = 0.52, the boiling point of this solution will be
(a) 102 °C
(b) 103 °C
(c) 101 °C
(d) 100 °C
Question. 200 mL of an aqueous solution of a protein contains its 1.26 g. The osmotic pressure of this solution at 300 K is found to be 2.57 × 10–3 bar. The molar mass of protein will be (R = 0.083 L bar mol–1 K–1)
(a) 51022 g mol–1
(b) 122044 g mol–1
(c) 31011 g mol–1
(d) 61038 g mol–1
Question. A solution of sucrose (molar mass = 342 g mol–1) has been prepared by dissolving 68.5 g of sucrose in 1000 g of water. The freezing point of the solution obtained will be (Kf for water = 1.86 K kg mol–1)
(a) – 0.372 °C
(b) – 0.520 °C
(c) + 0.372 °C
(d) – 0.570 °C
Question. During osmosis, flow of water through a semipermeable membrane is
(a) from solution having lower concentration only
(b) from solution having higher concentration only
(c) from both sides of semipermeable membrane with equal flow rates
(d) from both sides of semipermeable membrane with unequal flow rates.
Question. 1.00 g of a non-electrolyte solute (molar mass 250 g mol–1) was dissolved in 51.2 g of benzene. If the freezing point constant, Kf of benzene is 5.12 K kg mol–1, the freezing point of benzene will be lowered by
(a) 0.2 K
(b) 0.4 K
(c) 0.3 K
(d) 0.5 K
Question. A solution containing 10 g per dm3 of urea (molecular mass = 60 g mol–1) is isotonic with a 5% solution of a non-volatile solute. The molecular mass of this non-volatile solute is
(a) 200 g mol–1
(b) 250 g mol–1
(c) 300 g mol–1
(d) 350 g mol–1
Question. A solution of urea (mol. mass 56 g mol–1) boils at 100.18°C at the atmospheric pressure. If Kf and Kb for water are 1.86 and 0.512 K kg mol–1 respectively, the above solution will freeze at
(b) – 0.654°C
(d) – 6.54°C
Question. Pure water can be obtained from sea water by
(c) reverse osmosis
Question. From the colligative properties of solution, which one is the best method for the determination of molecular weight of proteins and polymers?
(a) Osmotic pressure
(b) Lowering in vapour pressure
(c) Lowering in freezing point
(d) Elevation in boiling point
Question. 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 of benzene. The vapour pressure of the solution is 600 mm of Hg. What is the molecular weight of solid substance?
Question. 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
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