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.
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