NEET Chemistry Solutions MCQs Set B

Question:   Osmotic pressure of solution containing 0.6 g urea and 3.42 g sugar in 100 ml at 27°C

• a) 492 atm
• b) 4.92 atm
• c) 49.2 atm
• d) 28.1 atm

Answer: 4.92 atm

Question: Which gas is most soluble in water?

• a) He
• b) H₂ 
• c) NH₃
• d) CO₂

Answer:  NH₃

Question:

Which is having highest elevation in boiling point?

• a) H₂O 
• b) Solution I
• c) Solution II
• d) Solution III

Answer: Solution III

Question:

Freezing point of solution is marked as

• a) A
• b) B
• c) C
• d) D

Answer: B

Question: van't Hoff factor for acetic acid in aqueous medium at infinite dilution is

• a) 2
• b) 1
• c) 1/2
• d) 3

Answer: 2

Question:  Correct order of freezing point of given solution

I. 0.1 M glucose    II. 0.2 M urea     III. 0.1 M NaCl     IV. 0.05 M CaCl₂

• a) I < II < III < IV
• b) I > II > III > IV
• c) III = II < IV < I
• d) IV > II > III > I

Answer: III = II < IV < I

Question:  Boiling point of 0.01 M AB₂ which is 10% dissociated in aqueous medium

 as A⁺² and B^–

• a) 273.006 K
• b) 373.006 K
• c) 0.006 K
• d) 272.006 K

Answer: 373.006 K

Question:  Vapour pressure diagram of some liquids plotted against temperature are shown below

Most volatile liquid

• a) A
• b) B
• c) C
• d) D

Answer: A

Question: At higher altitude, the boiling point of water is lowered because

• a) Atmosphere pressure is low
• b) Temperature is low
• c) Atmospheric pressure increases
• d) Water solidifies to ice

Answer: Atmosphere pressure is low

Question: During evaporation of liquid

• a) The temperature of liquid rises
• b) The temperature of liquid falls
• c) The temperature of liquid remains uneffected
• d) The liquid molecules becomes inert

Answer: The temperature of liquid falls

Question:  What is the concentration of NO₃^– ions when equal volumes of 0.1 M AgNO₃ and 0.1 M NaCl are mixed together?

• a) 0.1 N
• b) 0.25 M
• c) 0.05 M
• d) 0.2 M

Answer: 0.05 M

Question:  If any solute ‘A’ dimerises in water at 1 atm pressure and the boiling point of this solution is 100.52°C. If 2 moles of A is added to 1 kg of water and k_b for water is 0.52°C/molal, calculate the percentage association of A

• a) 50%
• b) 30%
• c) 25%
• d) 100%

Answer: 100%

Question:  Substance A tetramerises in water to the extent of 80%. A solution of 2.5 g of A in 100 g of water lowers the freezing point by 0.3°C. The molar mass of A is

• a) 122
• b) 31
• c) 244
• d) 62

Answer: 62

Question:   K₄[Fe(CN)₆ ] is supposed to be 40% dissociated when 1M solution prepared. Its boiling point is equal to another 20% mass by volume of non-electrolytic solution A. Considering molality = molarity. The molecular weight of A is

• a) 77
• b) 67
• c) 57
• d) 47

Answer: 77

More Questions........................................................

Question: Which one is not equal to zero for an ideal solution?

• a) ΔP = P_observed– P_Raoult
• b) ΔH_mix
• c) ΔS_mix
• d) ΔV_mix

Answer:  ΔS_mix

Question: What is the mole fraction of the solute in a 1.00 m aqueous solution?

• a) 0.0354
• b) 0.0177
• c) 0.177
• d) 1.770

Answer: 0.0177

Question:  The boiling point of 0.2 mol kg^–1 solution of X in water is greater than equimolal solution of Y in water. Which one of the following statements is true in this case? 

• a) Y is undergoing dissociation in water while X undergoes no change
• b) X is undergoing dissociation in water
• c) Molecular mass of X is greater than the molecular mass of Y
• d) Molecular mass of X is less than the molecular mass of Y

Answer: X is undergoing dissociation in water

Question:  Which one of the following electrolytes has the same value of van't Hoff's factor (i) as that of Al₂(SO₄)₃ (if all are 100% ionised)? 

• a) K₄[Fe(CN)₆] 
• b) K₂SO₄
• c) K₃[Fe(CN)₆]  
• d) Al(NO₃)₃

Answer: K₄[Fe(CN)₆] 

Question: Of the following 0.10m aqueous solutions, which one will exhibit the largest freezing point depression ?

• a) KCl
• b) C₆H₁₂O₆
• c) Al₂(SO₄)₃ 
• d) K₂SO₄

Answer:  Al₂(SO₄)₃ 

Question: The van't Hoff factor i for a compound which undergoes dissociation in one solvent and association in other solvent is respectively

• a) Greater than one and greater than one
• b) Less than one and greater than one
• c) Less than one and less than one
• d) Greater than one and less than one

Answer: Greater than one and less than one

Question:  p_A and p_B are the vapour pressure of pure liquid components, A and B, respectively of an ideal binary solution. If x_A represents the mole fraction of component A, the total pressure of the solution will be 

• a) p_B+ x_A(p_B–p_A)
• b) p_B+ x_A(p_A–p_B)
• c) p_A+ x_A(p_B–p_A) 
• d) p_A+ x_A(p_A–p_B)

Answer: p_B+ x_A(p_A–p_B)

Question:  The freezing point depression constant for water is –1.86° Cm ^–1. If 5.00 g Na₂SO₄ is dissolved in 45.0 g H₂O,the freezing point is changed by –3.82°C. Calculate the van't Hoff factor for Na₂SO₄ 

• a) 0.381
• b) 2.05
• c) 2.63
• d) 3.11

Answer: 2.63

Question:  A 0.1 molal aqueous solution of a weak acid is 30% ionized. If K_f for water is 1.86°C/m, the freezing point of the solution will be 

• a) –0.36°C 
• b) –0.24°C 
• c) –0.18°C
• d) –0.54°C

Answer: –0.24°C 

Question:  200 mL of an aqueous solution of a protein contains its 1.26g. 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) 31011 g mol^–1
• b) 61038 g mol^–1
• c) 51022 g mol^–1 
• d) 122044 g mol^–1

Answer: 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 (K_f for water = 1.86 K kg mol^–1)

• a) –0.372°C 
• b) –0.520°C
• c) +0.372°C 
• d) –0.570°C

Answer:  –0.372°C 

Question:  An aqueous solution is 1.00 molal in KI. Which change will cause the vapour pressure of the solution to increase?

• a) Addition of NaCl
• b) Additon of Na₂SO₄
• c) Addition of 1.00 molal KI
• d) Addition of water

Answer: Addition of water

Question:  A 0.0020 m aqueous solution of an ionic compound Co(NH₃)₅(NO₂)Cl freezes at –0.00732°C. Number of moles of ions which 1 mol of ionic compound produces on being dissolved in water will be (k1= –.86°C /m)

• a) 3
• b) 4
• c) 1
• d) 2

Answer: 2

Question: 0.5 molal aqueous solution of a weak acid (HX) is 20% ionized. If Kf for water is 1.86 K kg mol sup–1, the lowering in freezing point of the solution is

• a) –0.56 K
• b) –1.12 K
• c) 0.56 K
• d) 1.12K

Answer: 1.12K

Question:  A solution containing 10g per dm³ of urea (molecular mass = 60 g mol^–1) is isotonic with a 5% solution of a nonvolatile solute. The molecular mass of this non-volatile solute is 

• a) 250 g mol^–1 
• b) 300 g mol^–1
• c) 350 g mol^–1
• d) 200 g mol^–1

Answer:  300 g mol^–1

Question:  1.00 g of a non-electrolyte solute (molar mass 250g mol^–1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, K_f of benzene is 5.12 K kg mol^–1, the freezing point of benzene will be lowered by

• a) 0.4 K
• b) 0.3 K
• c) 0.5 K
• d) 0.2 K

Answer: 0.4 K

Question: A solution of acetone in ethanol

• a) Shows a negative deviation from Raoult's law
• b) Shows a positive deviation from Raoult's law
• c) Behaves like a near ideal solution
• d) Obeys Raoult's law

Answer: Shows a positive deviation from Raoult's law

Question: During osmosis, flow of water through a semi-permeable membrane is

• a) From solution having higher concentration only
• b) From both sides of semi-permeable membrane with equal flow rates
• c) From both sides of semi-permeable membrane with unequal flor rates
• d) From solution having lower concentration only

Answer: From both sides of semi-permeable membrane with unequal flor rates

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 moles of P and 2 moles of Q would be

• a) 140 torr
• b) 20 torr
• c) 68 torr
• d) 72 torr

Answer: 72 torr

Question:  A solution of urea (mol. mass 60g mol^-1) boils at 100.18°C at the atmospheric pressure. If k_f and k_b for water are 1.86 and 0.512K kg mol^–1 respectively, the above solution will freeze at 

• a) –6.54°C 
• b) 6.54°C 
• c) 0.654°C 
• d) –0.654°C

Answer: –0.654°C

Question:  A solution has a 1 : 4 mole ratio of pentane to hexane. The vapour pressure of the pure hydrocarbons at 20°C are 440 mm of Hg for pentane and 120 mm of Hg for hexane. The mole fraction of pentane in the vapour phase would be 

• a) 0.549
• b) 0.200
• c) 0.786
• d) 0.478

Answer: 0.478

Question: The mole fraction of the solute in one molal aqueous solution is

• a) 0.027
• b) 0.036
• c) 0.018
• d) 0.009

Answer: 0.018

Question: Which of the following compounds can be used as antifreeze in automobile radiators?

• a) Methyl alcohol
• b) Glycol
• c) Nitrophenol
• d) Ethyl alcohol

Answer: Glycol

Question: Mole fraction of the solute in a 1.00 molal aqueous solution is

• a) 1.7700
• b) 0.1770
• c) 0.0177
• d) 0.0344

Answer: 0.0177

Question:  1 × 10^–3 m solution of Pt(NH₃)₄Cl₄ in H₂O shows depression in freezing point by 0.0054°C. The structure of the compound will be (Given K_f = 1.860 km^–1)

• a) [Pt(NH₃)₄]Cl₄   
• b) [Pt(NH₃)₃Cl]Cl₃
• c) [Pt(NH₃)₂Cl₂]Cl₂
• d) Pt(NH₃)Cl₃]Cl

Answer: [Pt(NH₃)₂Cl₂]Cl₂

Question:  Which of the following salt has the same value of van’t Hoff’s factor i as that of K₃[Fe(CN)₆]?

• a) Na₂SO₄
• b) Al(NO₃)₃
• c) Al₂(SO₄)₃  
• d) NaCl

Answer:  Al(NO₃)₃

Question:  At 25°C, the highest osmotic pressure is exhibited by 0.1 M solution of

• a) Glucose
• b) Urea
• c) CaCl₂
• d) KCl

Answer:  CaCl₂

Question: According to Raoult’s law, the relative lowering of vapour pressure for a solution is equal to

• a) Mole fraction of solute
• b) Mole fraction of solvent
• c) Moles of solute
• d) Moles of solvent

Answer: Mole fraction of solute

Question: The concentration units, independent of temperature, would be

• a) Normality
• b) Weight volume percent
• c) Molality
• d) Molarity

Answer: Molality

Question:  The vapour pressure of CCI₄ at 25ºC is 143 mm Hg. If 0.5 gm of a non-volatile solute (mol. weight = 65) is dissolved in 100 g CCI₄ , the vapour pressure of the solution will be

• a) 199.34 mm Hg
• b) 143.99 mm Hg
• c) 141.43 mm Hg
• d) 94.39 mm Hg

Answer: 141.43 mm Hg

Question: In liquid-gas equilibrium, the pressure of vapours above the liquid is constant at

• a) Constant temperature
• b) Low temperature
• c) High temperature
• d) None of these

Answer: Constant temperature

Question:  What is the molarity of H₂SO₄ solution, that has a density 1.84 gm/cc at 35ºC and contains 98% by weight of solute?

• a) 18.4 M
• b) 18 M
• c) 4.18 M
• d) 8.14 M

Answer: 18.4 M

Question: A 5% (w/v) solution of cane sugar (mol. wt. = 342) is isotonic with 1% (w/v) solution of a substance X. The molecular weight of X is

• a) 68.4
• b) 171.2
• c) 34.2
• d) 136.8

Answer: 68.4

Question: The vapour pressure of a solvent decreased by 10 mm of mercury when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent if the decrease in the vapour pressure is to be 20 mm of mercury?

• a) 0.4
• b) 0.6
• c) 0.8
• d) 0.2

Answer: 0.6

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

• a) 10.1
• b) 100
• c) 1.01
• d) 1000

Answer: 100

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?

• a) 65.2
• b) 59.6
• c) 49.50
• d) 79.8

Answer: 65.2

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

Answer: Osmotic pressure

Question: Molarity of liquid HCl, if density of solution is 1.17 gm/cc is

• a) 36.5
• b) 18.25
• c) 32.05
• d) 42.10

Answer: 32.05

Question:  A solution contains non volatile solute of molecular mass M₂. Which of the following can be used to calculate the molecular mass of solute in terms of osmotic pressure? (m₂- mass of solute, V - volume of solution,π - osmotic pressure)

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

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

Answer: A - B attraction force remains same as A - A and B - B

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

Answer: Osmotic pressure

Question: Camphor is often used in molecular mass determination because

• a) It is readily available
• b) It has very high cryoscopic constant
• c) It is volatile
• d) It is solvent for organic substances

Answer: It has very high cryoscopic constant

Question: The vapour pressure of a solvent decreased by 10 mm of mercury when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent if the decrease in the vapour pressure is to be 20 mm of mercury?

• a) 0.4
• b) 0.6
• c) 0.8
• d) 0.2

Answer: 0.6

Question:  Formation of a solution from two components can be considered as

Solution so formed will be ideal if

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: In liquid-gas equilibrium, the pressure of vapours above the liquid is constant at

• a) Constant temperature
• b) Low temperature
• c) High temperature
• d) None of these

Answer: Constant temperature

Question: Which of the following compounds can be used as antifreeze in automobile radiators?

• a) Methyl alcohol
• b) Glycol
• c) Nitrophenol
• d) Ethyl alcohol

Answer: Glycol