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
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