Chapter 9: Solutions — Online MCQ Test
CHEMISTRY · CLASS 11th · Tamil Nadu State Board
Practice Chapter 9: Solutions with a free chapter-wise online MCQ test.
This chapter covers: Focusing on liquid mixtures this chapter details solution types concentration units Raoult law and ideal non-ideal solutions. Students study colligative properties vapor pressure l....
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Chapter 9: Solutions — Important Questions & Answers
Which concentration unit represents the number of moles of solute per kilogram of solvent?
- A. Molarity
- B. Molality
- C. Normality
- D. Mole fraction
Answer: B. Molality
Molality is defined as the number of moles of solute dissolved in 1 kg of solvent.
Molality is defined as the number of moles of solute dissolved in 1 kg of solvent.
An ideal solution is one that obeys:
- A. Raoult's law over the entire range of concentration
- B. Henry's law
- C. Dalton's law
- D. None of these
Answer: A. Raoult's law over the entire range of concentration
An ideal solution obeys Raoult's law at all concentrations and temperatures.
An ideal solution obeys Raoult's law at all concentrations and temperatures.
In a non-ideal solution, which of the following is true for a positive deviation from Raoult's law?
- A. ΔHmix = 0
- B. ΔVmix = 0
- C. ΔHmix > 0
- D. A-B interactions are stronger than A-A or B-B
Answer: C. ΔHmix > 0
For positive deviation, intermolecular forces are weaker, leading to endothermic mixing (ΔHmix > 0) and expansion in volume (ΔVmix > 0).
For positive deviation, intermolecular forces are weaker, leading to endothermic mixing (ΔHmix > 0) and expansion in volume (ΔVmix > 0).
Two liquids A and B form an azeotropic mixture at a specific composition. This means:
- A. They can be separated by fractional distillation
- B. They have different boiling points
- C. They distill at the same temperature without change in composition
- D. They obey Raoult's law perfectly
Answer: C. They distill at the same temperature without change in composition
Azeotropes are constant boiling mixtures where the liquid and vapor phases have identical compositions.
Azeotropes are constant boiling mixtures where the liquid and vapor phases have identical compositions.
A solution contains 1 mole of solute A and 3 moles of solvent B. The mole fraction of solute A is:
- A. 0.75
- B. 0.25
- C. 0.33
- D. 0.20
Answer: B. 0.25
Mole fraction of A = moles of A / (moles of A + moles of B) = 1 / (1 + 3) = 1/4 = 0.25.
Mole fraction of A = moles of A / (moles of A + moles of B) = 1 / (1 + 3) = 1/4 = 0.25.