Here below some basic MCQ’s about “Concentration Terms” which is explained in details. Let’s check one by one.
1. Which of the following is an example of a concentration term that is independent of temperature?
a) Molarity
b) Molality
c) Normality
d) Volume percent
Answer: b) Molality
Explanation:
Molality is defined as the number of moles of solute per kilogram of solvent. Since it is based on mass (kg) rather than volume, it is independent of temperature. On the other hand, molarity (moles/liter) and normality depend on volume, which can change with temperature.
2. Which of the following concentration terms expresses the number of moles of solute present in one liter of solution?
a) Molality
b) Molarity
c) Normality
d) Mole fraction
Answer: b) Molarity
Explanation:
Molarity (M) is defined as the number of moles of solute divided by the volume of the solution in liters. It is temperature-dependent as it involves volume, which can expand or contract with temperature changes.
3. A solution is prepared by dissolving 10 g of NaCl in 90 g of water. The molality of the solution is closest to:
(Molecular weight of NaCl = 58.5 g/mol)
a) 1.71 mol/kg
b) 1.53 mol/kg
c) 1.90 mol/kg
d) 2.15 mol/kg
Answer: a) 1.71 mol/kg
4. What is the mole fraction of ethanol in a solution containing 46 g of ethanol (C₂H₅OH) and 180 g of water?
(Molecular weight of ethanol = 46 g/mol, water = 18 g/mol)
a) 0.20
b) 0.30
c) 0.40
d) 0.25
Answer: a) 0.20
5. A solution has a molarity of 2 M and density of 1.25 g/mL. What is the molality of the solution if the molar mass of the solute is 58.5 g/mol?
a) 1.9 mol/kg
b) 2.5 mol/kg
c) 3.4 mol/kg
d) 4.1 mol/kg
Answer: b) 2.5 mol/kg
6. What is the normality of a solution containing 5 g of NaOH in 500 mL of solution? (Molar mass of NaOH = 40 g/mol)
a) 0.2 N
b) 0.25 N
c) 0.5 N
d) 1 N
Answer: b) 0.25 N
7. The percentage by mass of solute in a solution is 20%. What is the mole fraction of the solute if the molecular mass of the solute is 50 g/mol and the molecular mass of the solvent is 18 g/mol?
a) 0.059
b) 0.121
c) 0.252
d) 0.050
Answer: a) 0.059
8. Which of the following concentration terms is affected by changes in both the solute and solvent amount?
a) Molality
b) Mole fraction
c) Molarity
d) Normality
Answer: c) Molarity
Explanation:
Molarity is the number of moles of solute per liter of solution. Since it depends on the volume of the solution (which includes both solute and solvent), any change in either the solute or solvent can affect the molarity.
9. A 5% (w/v) glucose solution contains how many grams of glucose in 500 mL of the solution?
a) 5 g
b) 10 g
c) 25 g
d) 50 g
Answer: c) 25 g
10. The molality of a solution is 3 mol/kg, and the mass of the solvent is 400 g. What is the mass of the solute?
(Molecular weight of solute = 58.5 g/mol)
a) 58.5 g
b) 70.2 g
c) 80.1 g
d) 88.2 g
Answer: b) 70.2 g
11. A solution contains 0.5 mol of NaCl dissolved in 250 mL of solution. What is the molarity of the solution?
a) 1 M
b) 2 M
c) 0.5 M
d) 4 M
Answer: b) 2 M
12. A solution contains 18 g of glucose (C₆H₁₂O₆) dissolved in 90 g of water. What is the molality of the solution?
(Molecular weight of glucose = 180 g/mol)
a) 0.1 mol/kg
b) 1.0 mol/kg
c) 0.2 mol/kg
d) 2.0 mol/kg
Answer: a) 0.1 mol/kg
13. Which of the following solutions will have the highest molarity if all contain 1 mol of solute?
a) 0.5 L of solution
b) 1 L of solution
c) 2 L of solution
d) 3 L of solution
Answer: a) 0.5 L of solution
Explanation:
Molarity (M) = moles of solute / volume of solution.
14. What will be the molarity of a solution prepared by dissolving 8 g of NaOH in 500 mL of solution?
(Molar mass of NaOH = 40 g/mol)
a) 0.1 M
b) 0.2 M
c) 0.4 M
d) 0.6 M
Answer: c) 0.4 M
15. A solution is prepared by dissolving 5 g of KCl in 100 g of water. The mole fraction of KCl in the solution is:
(Molecular weight of KCl = 74.5 g/mol, water = 18 g/mol)
a) 0.01
b) 0.02
c) 0.05
d) 0.10
Answer: a) 0.01
16. If the molarity of a solution is 0.5 M and the volume of the solution is doubled, what will be the new molarity?
a) 0.25 M
b) 0.5 M
c) 1 M
d) 2 M
Answer: a) 0.25 M
17. What is the normality of a solution of sulfuric acid (H₂SO₄) if the molarity is 2 M?
a) 1 N
b) 2 N
c) 4 N
d) 6 N
Answer: c) 4 N
Explanation:
Normality (N) = molarity (M) × n-factor.
For H₂SO₄, the n-factor is 2 (as it can donate 2 H⁺ ions).
Normality = 2 M×2=4 N
18. A solution is made by dissolving 1 mol of a solute in 100 g of water. If the solution’s density is 1.2 g/mL, what is the molarity of the solution?
a) 5 M
b) 10 M
c) 15 M
d) 20 M
Answer: b) 10 M
19. A solution is prepared by dissolving 4 g of NaOH in 250 mL of solution. What is the molarity of the solution?
(Molecular mass of NaOH = 40 g/mol)
a) 0.1 M
b) 0.2 M
c) 0.4 M
d) 0.5 M
Answer: c) 0.4 M
20. If 20 g of NaOH is dissolved in 200 g of water, what is the molality of the solution?
(Molecular mass of NaOH = 40 g/mol)
a) 1 mol/kg
b) 2.5 mol/kg
c) 3 mol/kg
d) 5 mol/kg
Answer: b) 2.5 mol/kg
21. Which of the following is a concentration term that depends on the mass of the solvent but not on the volume of the solution?
a) Molarity
b) Molality
c) Normality
d) Weight percent
Answer: b) Molality
Explanation:
Molality is defined as the number of moles of solute per kilogram of solvent, so it is independent of the volume of the solution and depends only on the mass of the solvent.
22. What is the molality of a solution in which 5 moles of solute are dissolved in 2 kg of solvent?
a) 2.5 mol/kg
b) 1.5 mol/kg
c) 5 mol/kg
d) 10 mol/kg
Answer: a) 2.5 mol/kg
23. A solution is prepared by dissolving 2 mol of solute in 500 mL of solution. What is the molarity of the solution?
a) 4 M
b) 2 M
c) 1 M
d) 0.5 M
Answer: a) 4 M
24. The mole fraction of solute in a binary solution is 0.2. What is the mole fraction of the solvent?
a) 0.2
b) 0.3
c) 0.8
d) 1.0
Answer: c) 0.8
25. A solution of glucose is 10% (w/w). What is the mass of glucose in 500 g of this solution?
a) 50 g
b) 10 g
c) 100 g
d) 20 g
Answer: a) 50 g
26. If the molarity of a solution is 3 M, what is the number of moles of solute present in 2 L of the solution?
a) 3 mol
b) 6 mol
c) 1.5 mol
d) 0.5 mol
Answer: b) 6 mol
Explanation:
Molarity = moles of solute / volume of solution in liters
Moles of solute = Molarity × Volume
Moles of solute = 3 M×2 L=6 mol
27. If 50 mL of 0.5 M HCl is diluted to 250 mL, what will be the new molarity of the solution?
a) 0.1 M
b) 0.2 M
c) 0.5 M
d) 1 M
Answer: a) 0.1 M
28. What is the mole fraction of water in a solution containing 18 g of water and 46 g of ethanol?
(Molecular weight of water = 18 g/mol, ethanol = 46 g/mol)
a) 0.5
b) 0.33
c) 0.67
d) 0.75
Answer: a) 0.5
29. Which of the following solutions has the highest molality?
a) 1 M solution of glucose
b) 1 M solution of NaCl
c) 1 M solution of H₂SO₄
d) 1 M solution of KCl
Answer: a) 1 M solution of glucose
Explanation:
Molality depends on the number of moles of solute per kg of solvent. Glucose has a higher molar mass compared to NaCl, H₂SO₄, and KCl, so for the same molarity, the solution with the largest molecular mass will have the highest molality because it results in fewer moles per liter of solution, which means more mass of solvent.
30. The normality of 1 M H₂SO₄ solution is:
a) 1 N
b) 2 N
c) 0.5 N
d) 0.25 N
Answer: b) 2 N
Explanation:
Normality (N) = Molarity (M) × n-factor
For H₂SO₄, the n-factor is 2 (as it can donate 2 H⁺ ions).
Normality = 1 M×2=2 N
31. What is the weight percent of solute in a solution containing 25 g of solute and 75 g of solvent?
a) 25%
b) 50%
c) 33%
d) 20%
Answer: a) 25%
32. Which of the following terms is dimensionless?
a) Molarity
b) Molality
c) Mole fraction
d) Normality
Answer: c) Mole fraction
Explanation:
Mole fraction is a ratio of moles of solute to the total moles in the solution, so it has no units and is dimensionless.
33. What is the mole fraction of solute in a solution that contains 2 moles of solute and 8 moles of solvent?
a) 0.2
b) 0.25
c) 0.4
d) 0.8
Answer: b) 0.25
34. What will be the molality of a solution prepared by dissolving 9.8 g of H₂SO₄ in 250 g of water?
(Molecular weight of H₂SO₄ = 98 g/mol)
a) 0.1 mol/kg
b) 0.2 mol/kg
c) 0.4 mol/kg
d) 0.5 mol/kg
Answer: b) 0.4 mol/kg
35. If the mole fraction of water in a solution is 0.75, what is the mole fraction of the solute?
a) 0.75
b) 0.50
c) 0.25
d) 0.10
Answer: c) 0.25
Explanation:
In a binary solution, the sum of mole fractions of the solute and solvent is 1.
Mole fraction of solute = 1−0.75=0.25
36. A 10% (w/w) NaCl solution contains how many grams of NaCl in 200 g of the solution?
a) 10 g
b) 20 g
c) 30 g
d) 40 g
Answer: b) 20 g
37. Which of the following concentration terms is used when dealing with electrolytes?
a) Molarity
b) Molality
c) Normality
d) Mole fraction
Answer: c) Normality
Explanation:
Normality is often used for electrolytes because it accounts for the equivalents of reactive ions (like H⁺ or OH⁻) per liter of solution, which is important for titrations and reactions involving acids and bases.
38. Which of the following solutions has the highest concentration if all contain the same number of moles of solute?
a) 1 L of solution
b) 2 L of solution
c) 0.5 L of solution
d) 5 L of solution
Answer: c) 0.5 L of solution
Explanation:
Molarity is defined as the number of moles of solute per liter of solution. The smaller the volume of the solution, the higher the molarity. So, the 0.5 L solution will have the highest concentration.
39. If 5 moles of solute are dissolved in 10 kg of solvent, what is the molality of the solution?
a) 0.1 mol/kg
b) 0.5 mol/kg
c) 1 mol/kg
d) 2 mol/kg
Answer: b) 0.5 mol/kg
40. A solution of 1 M HCl has a density of 1.1 g/mL. What is the molality of this solution?
(Molecular weight of HCl = 36.5 g/mol)
a) 0.98 mol/kg
b) 1.0 mol/kg
c) 1.1 mol/kg
d) 1.5 mol/kg
Answer: a) 0.98 mol/kg
41. Which of the following solutions has the lowest molality?
a) 1 M NaOH solution
b) 1 M glucose solution
c) 1 M HCl solution
d) 1 M KCl solution
Answer: a) 1 M NaOH solution
Explanation:
Molality depends on the molar mass of the solute. NaOH has a lower molar mass than glucose, HCl, and KCl, so for the same molarity, it will have the lowest molality.
42. What will be the molarity of a solution prepared by dissolving 58.5 g of NaCl in enough water to make 500 mL of solution?
(Molar mass of NaCl = 58.5 g/mol)
a) 1 M
b) 2 M
c) 0.5 M
d) 0.25 M
Answer: b) 2 M
43. A 2 M solution of NaOH is diluted to 4 L. If the final concentration is 0.5 M, what was the original volume of the solution?
a) 1 L
b) 2 L
c) 0.5 L
d) 4 L
Answer: a) 1 L
44. A solution has 0.1 mole fraction of solute. What is the mole fraction of solvent in this solution?
a) 0.1
b) 0.5
c) 0.9
d) 1.0
Answer: c) 0.9
Explanation:
Mole fraction of solvent = 1−0.1=0.9
45. How many moles of solute are present in 0.5 L of 1 M HCl solution?
a) 0.25 mol
b) 0.5 mol
c) 1 mol
d) 2 mol
Answer: b) 0.5 mol
Explanation:
Moles of solute = molarity × volume (in liters)
Moles of solute = 1 M×0.5 L=0.5 mol
46. Which of the following concentration terms is temperature-dependent?
a) Molality
b) Mole fraction
c) Molarity
d) Weight percent
Answer: c) Molarity
Explanation:
Molarity depends on the volume of the solution, and volume can change with temperature, making molarity a temperature-dependent concentration term.
47. The molality of a solution of glucose in water is 1 mol/kg. How many grams of glucose are present in 1 kg of solvent?
(Molar mass of glucose = 180 g/mol)
a) 180 g
b) 90 g
c) 360 g
d) 45 g
Answer: a) 180 g
Explanation:
1 mol of glucose weighs 180 g, and since the molality is 1 mol/kg, there are 180 g of glucose in 1 kg of water.
48. What is the molality of a solution in which 15 g of NaOH is dissolved in 1 kg of water?
(Molecular weight of NaOH = 40 g/mol)
a) 0.25 mol/kg
b) 0.375 mol/kg
c) 0.5 mol/kg
d) 1 mol/kg
Answer: b) 0.375 mol/kg
49. A solution contains 5 g of urea in 95 g of water. What is the weight percent of urea in the solution?
a) 5%
b) 10%
c) 15%
d) 20%
Answer: a) 5%
50. What is the molarity of a solution prepared by dissolving 20 g of NaOH in 500 mL of solution?
(Molecular weight of NaOH = 40 g/mol)
a) 0.5 M
b) 1.0 M
c) 2.0 M
d) 3.0 M
Answer: c) 1.0 M
51. If 2 moles of HCl are dissolved in 2 L of solution, what is the molarity of the solution?
a) 0.5 M
b) 1.0 M
c) 2.0 M
d) 4.0 M
Answer: b) 1.0 M
52. The normality of a solution containing 49 g of H₂SO₄ in 1 L of solution is:
(Molecular weight of H₂SO₄ = 98 g/mol)
a) 0.5 N
b) 1.0 N
c) 2.0 N
d) 3.0 N
Answer: a) 1.0 N
Explanation:
Moles of H₂SO₄ = 4998=0.5 mol
For H₂SO₄, n-factor = 2 (because it releases 2 H⁺ ions).
Normality = Molarity × n-factor
Molarity = 0.5 mol/L and thus, Normality = 0.5×2=1.0 N
53. A 5 M NaCl solution is diluted to 1 L. If the final concentration is 0.5 M, what was the initial volume of the solution?
a) 0.1 L
b) 0.2 L
c) 0.5 L
d) 1 L
Answer: a) 0.1 L
Explanation:
Using the dilution formula:
M1V1=M2V2
54. Which of the following will have the highest concentration of H⁺ ions in an aqueous solution?
a) 0.1 M HCl
b) 0.2 M CH₃COOH
c) 0.1 M NaOH
d) 0.1 M NH₄OH
Answer: a) 0.1 M HCl
Explanation:
HCl is a strong acid, and it dissociates completely in aqueous solution, giving a higher concentration of H⁺ ions compared to the weak acids (like CH₃COOH) or bases (like NaOH and NH₄OH).
55. The molality of a solution prepared by dissolving 10 g of NaCl in 100 g of water is approximately:
(Molecular weight of NaCl = 58.5 g/mol)
a) 1 mol/kg
b) 1.71 mol/kg
c) 2 mol/kg
d) 0.5 mol/kg
Answer: b) 1.71 mol/kg
56. Which of the following solutions will have the highest boiling point elevation?
a) 1 M glucose
b) 1 M NaCl
c) 1 M MgCl₂
d) 1 M urea
Answer: c) 1 M MgCl₂
Explanation:
Boiling point elevation depends on the number of particles in solution. MgCl₂ dissociates into three ions (Mg²⁺ and 2 Cl⁻), giving more particles in solution than NaCl (which dissociates into two ions) or glucose/urea (which do not dissociate).
57. What is the normality of a 0.5 M H₂SO₄ solution?
a) 0.5 N
b) 1.0 N
c) 1.5 N
d) 2.0 N
Answer: b) 1.0 N
Explanation:
Normality = Molarity × n-factor
For H₂SO₄, the n-factor is 2 (because it releases 2 H⁺ ions).
Normality = 0.5×2=1.0 N
58. What is the mole fraction of urea in a solution containing 180 g of water and 60 g of urea?
(Molecular weight of water = 18 g/mol, urea = 60 g/mol)
a) 0.2
b) 0.33
c) 0.5
d) 0.67
Answer: b) 0.33
59. A solution has 0.5 mole fraction of solute. What is the mole fraction of the solvent?
a) 0.1
b) 0.5
c) 1.0
d) 2.0
Answer: b) 0.5
Explanation:
In a binary solution, the sum of mole fractions of solute and solvent is 1.
Mole fraction of solvent = 1−0.5=0.5
60. Which concentration term is best suited for expressing the concentration of solutions that undergo temperature changes?
a) Molarity
b) Molality
c) Normality
d) Weight percent
Answer: b) Molality
Explanation:
Molality is based on the mass of solvent, which is independent of temperature, making it the best choice when temperature variations are involved.
61. What is the molarity of a solution containing 98 g of H₂SO₄ in 500 mL of solution?
(Molecular weight of H₂SO₄ = 98 g/mol)
a) 1 M
b) 2 M
c) 3 M
d) 4 M
Answer: b) 2 M
62. Which of the following will show the highest freezing point depression?
a) 1 M glucose
b) 1 M NaCl
c) 1 M AlCl₃
d) 1 M K₂SO₄
Answer: c) 1 M AlCl₃
Explanation:
Freezing point depression depends on the number of particles in solution. AlCl₃ dissociates into 4 ions (Al³⁺ and 3 Cl⁻), giving the highest particle concentration compared to NaCl (2 ions), K₂SO₄ (3 ions), and glucose (which doesn’t dissociate).
63. A 0.2 M solution of NaOH has a density of 1.02 g/mL. What is the molality of the solution?
(Molecular weight of NaOH = 40 g/mol)
a) 0.21 mol/kg
b) 0.23 mol/kg
c) 0.25 mol/kg
d) 0.27 mol/kg
Answer: b) 0.23 mol/kg
64. If 1.5 moles of solute are dissolved in 3 kg of solvent, what is the molality of the solution?
a) 0.25 mol/kg
b) 0.5 mol/kg
c) 0.75 mol/kg
d) 1 mol/kg
Answer: b) 0.5 mol/kg
65. How many grams of NaOH are needed to prepare 250 mL of a 2 M solution?
(Molecular weight of NaOH = 40 g/mol)
a) 10 g
b) 15 g
c) 20 g
d) 25 g
Answer: d) 20 g
Explanation:
Moles of NaOH = Molarity × Volume = 2 mol/L×0.25 L=0.5 mol
Mass of NaOH = 0.5 mol×40 g/mol=20 g
66. A solution contains 3 moles of solute in 4 kg of solvent. What is the molality of the solution?
a) 0.5 mol/kg
b) 0.75 mol/kg
c) 1.0 mol/kg
d) 1.25 mol/kg
Answer: d) 0.75 mol/kg
67. Which of the following solutions has the lowest freezing point?
a) 1 M NaCl
b) 1 M glucose
c) 1 M AlCl₃
d) 1 M K₂SO₄
Answer: c) 1 M AlCl₃
Explanation:
The depression in freezing point depends on the number of particles. AlCl₃ dissociates into 4 ions, which leads to the highest freezing point depression among the given options.
68. How many moles of solute are present in 2 L of a 0.5 M solution?
a) 0.25 mol
b) 0.5 mol
c) 1 mol
d) 2 mol
Answer: c) 1 mol
Explanation:
Moles of solute = Molarity × Volume
Moles of solute = 0.5 M×2 L=1 mol
69. What is the mole fraction of solute in a solution containing 0.2 moles of solute and 0.8 moles of solvent?
a) 0.1
b) 0.2
c) 0.5
d) 0.8
Answer: b) 0.2
70. Which of the following is used to express the concentration of a solution for non-ideal solutions where volume is not additive?
a) Molarity
b) Molality
c) Mole fraction
d) Normality
Answer: c) Mole fraction
Explanation:
Mole fraction is ideal for non-ideal solutions where volume is not additive because it’s based on the number of moles and is independent of volume.
71. What is the molality of a solution prepared by dissolving 10 g of NaOH in 500 g of water?
(Molecular weight of NaOH = 40 g/mol)
a) 0.25 mol/kg
b) 0.5 mol/kg
c) 1 mol/kg
d) 2 mol/kg
Answer: c) 0.5 mol/kg
72. Which concentration term is suitable when dealing with temperature changes?
a) Molarity
b) Molality
c) Normality
d) Weight percent
Answer: b) Molality
Explanation:
Molality is based on the mass of the solvent, which remains unaffected by temperature, making it ideal for situations involving temperature changes.
73. What is the molarity of a solution prepared by dissolving 20 g of NaOH in 250 mL of solution?
(Molecular weight of NaOH = 40 g/mol)
a) 0.5 M
b) 1 M
c) 2 M
d) 4 M
Answer: c) 2 M
74. The molality of a solution is expressed as:
a) Moles of solute per liter of solvent
b) Moles of solute per kilogram of solvent
c) Moles of solute per liter of solution
d) Moles of solute per milliliter of solution
Answer: b) Moles of solute per kilogram of solvent
Explanation:
Molality is defined as the number of moles of solute dissolved in 1 kilogram of solvent.
75. What is the normality of a 2 M H₂SO₄ solution?
a) 1 N
b) 2 N
c) 3 N
d) 4 N
Answer: d) 4 N
76. What is the mole fraction of ethanol in a solution containing 46 g of ethanol and 180 g of water?
(Molecular weight of ethanol = 46 g/mol, water = 18 g/mol)
a) 0.2
b) 0.33
c) 0.5
d) 0.67
Answer: a) 0.2
77. If the molality of a solution is 2 mol/kg, how many moles of solute are present in 4 kg of solvent?
a) 1 mol
b) 2 mol
c) 4 mol
d) 8 mol
Answer: d) 8 mol
78. What is the molarity of a solution prepared by dissolving 10 g of NaOH in 2 L of solution?
(Molecular weight of NaOH = 40 g/mol)
a) 0.1 M
b) 0.125 M
c) 0.25 M
d) 0.5 M
Answer: a) 0.125 M
79. Which of the following solutions will have the highest osmotic pressure at the same concentration?
a) Glucose solution
b) NaCl solution
c) K₂SO₄ solution
d) Urea solution
Answer: c) K₂SO₄ solution
Explanation:
Osmotic pressure is directly proportional to the number of particles in solution. K₂SO₄ dissociates into 3 ions (2 K⁺ and SO₄²⁻), which gives the highest number of particles and, therefore, the highest osmotic pressure.
80. The molarity of a solution changes with:
a) Pressure
b) Volume
c) Temperature
d) Solute amount
Answer: c) Temperature
Explanation:
Molarity depends on the volume of the solution, which changes with temperature, making it temperature-dependent.
81. What is the normality of a solution containing 40 g of NaOH in 1 L of solution?
(Molecular weight of NaOH = 40 g/mol)
a) 0.5 N
b) 1 N
c) 2 N
d) 4 N
Answer: b) 1 N
82. If 58.5 g of NaCl is dissolved in 500 mL of solution, what is the molarity?
(Molecular weight of NaCl = 58.5 g/mol)
a) 1 M
b) 2 M
c) 3 M
d) 4 M
Answer: b) 2 M
83. A solution has a density of 1.12 g/mL. If the molarity of the solution is 1 M and the solute has a molar mass of 60 g/mol, what is the molality of the solution?
a) 0.89 mol/kg
b) 1 mol/kg
c) 1.12 mol/kg
d) 2 mol/kg
Answer: a) 0.89 mol/kg
84. Which of the following is independent of temperature?
a) Molarity
b) Molality
c) Normality
d) Volume percent
Answer: b) Molality
Explanation:
Molality is based on the mass of the solvent, which does not change with temperature, unlike molarity or normality which depend on the volume of the solution.
85. A solution contains 2 moles of HCl in 500 mL of solution. What is its molarity?
a) 0.5 M
b) 1 M
c) 2 M
d) 4 M
Answer: d) 4 M
86. What is the molality of a solution prepared by dissolving 5 g of NaOH in 200 g of water?
(Molecular weight of NaOH = 40 g/mol)
a) 0.625 mol/kg
b) 1 mol/kg
c) 0.5 mol/kg
d) 0.125 mol/kg
Answer: a) 0.625 mol/kg
87. What is the mole fraction of a solute in a solution where 2 moles of solute are dissolved in 8 moles of solvent?
a) 0.1
b) 0.2
c) 0.25
d) 0.8
Answer: b) 0.2
88. If 1 mole of glucose is dissolved in 1 kg of water, the freezing point depression of the solution is:
(K_f for water = 1.86°C kg/mol)
a) 1.86°C
b) 3.72°C
c) 5.58°C
d) 7.44°C
Answer: a) 1.86°C
Explanation:
Freezing point depression, ΔTf=Kf×molality
Molality = 1 mol/kg
ΔTf=1.86 °C×1=1.86 °C
89. Which of the following solutions will have the lowest boiling point?
a) 1 M NaCl
b) 1 M glucose
c) 1 M AlCl₃
d) 1 M K₂SO₄
Answer: b) 1 M glucose
Explanation:
Boiling point elevation depends on the number of particles. Since glucose does not dissociate in solution, it has the fewest particles, leading to the lowest boiling point elevation.
90. What is the molality of a solution prepared by dissolving 10 g of glucose (C₆H₁₂O₆) in 90 g of water?
(Molecular weight of glucose = 180 g/mol)
a) 0.5 mol/kg
b) 0.62 mol/kg
c) 1 mol/kg
d) 1.5 mol/kg
Answer: b) 0.62 mol/kg
91. A solution has a density of 1.1 g/mL and contains 20% by weight of NaCl. What is the molality of the solution?
(Molecular weight of NaCl = 58.5 g/mol)
a) 3.3 mol/kg
b) 4.5 mol/kg
c) 5.7 mol/kg
d) 6.2 mol/kg
Answer: b) 4.5 mol/kg
92. Which of the following is true for a solution with a molarity of 1 M?
a) It contains 1 mole of solute per 1 kg of solvent
b) It contains 1 mole of solute per 1 liter of solvent
c) It contains 1 mole of solute per 1 liter of solution
d) It contains 1 mole of solute per 1 mL of solution
Answer: c) It contains 1 mole of solute per 1 liter of solution
Explanation:
Molarity is defined as the number of moles of solute per liter of solution.
93. If 0.5 moles of NaOH is dissolved in 2 liters of solution, what is the molarity?
a) 0.25 M
b) 0.5 M
c) 1 M
d) 2 M
Answer: a) 0.25 M
94. A solution is prepared by dissolving 36.5 g of HCl in water to make 1 L of solution. What is its molarity?
(Molecular weight of HCl = 36.5 g/mol)
a) 0.5 M
b) 1 M
c) 2 M
d) 3 M
Answer: b) 1 M
95. What is the normality of a solution prepared by dissolving 40 g of NaOH in 500 mL of solution?
(Molecular weight of NaOH = 40 g/mol)
a) 1 N
b) 2 N
c) 3 N
d) 4 N
Answer: b) 2 N
96. If 2.7 g of AlCl₃ is dissolved in water to prepare 200 mL of solution, what is the molarity of the solution?
(Molecular weight of AlCl₃ = 133.5 g/mol)
a) 0.1 M
b) 0.2 M
c) 0.3 M
d) 0.4 M
Answer: a) 0.1 M
97. If 0.25 moles of solute is dissolved in 500 g of water, what is the molality of the solution?
a) 0.25 mol/kg
b) 0.5 mol/kg
c) 0.75 mol/kg
d) 1 mol/kg
Answer: b) 0.5 mol/kg
98. What is the mole fraction of water in a solution containing 18 g of water and 46 g of ethanol?
(Molecular weight of water = 18 g/mol, ethanol = 46 g/mol)
a) 0.25
b) 0.5
c) 0.75
d) 0.33
Answer: b) 0.5
99. What is the boiling point elevation for a solution containing 0.5 mol of NaCl in 1 kg of water?
(K_b for water = 0.52°C kg/mol)
a) 0.26°C
b) 0.52°C
c) 1.04°C
d) 1.56°C
Answer: c) 1.04°C
100. The freezing point depression for a 1 M NaCl solution is greater than that for a 1 M glucose solution because:
a) NaCl has a higher molecular weight than glucose
b) NaCl dissociates into ions, increasing the number of particles
c) Glucose dissociates into ions, increasing the number of particles
d) NaCl has a lower molecular weight than glucose
Answer: b) NaCl dissociates into ions, increasing the number of particles
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