Chapter-1 Solutions — Online MCQ Test
CHEMISTRY · Grade 12 · CBSE(NCERT)
Practice Chapter-1 Solutions with a free chapter-wise online MCQ test.
This chapter covers: types of solutions - concentration terms - Henry's Law - Raoult's Law - colligative properties.
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Chapter-1 Solutions — Important Questions & Answers
A solution is a homogeneous mixture of two or more substances. Which of the following is NOT a characteristic of a solution?
- A. It has a uniform composition throughout
- B. The solute particles are visible under a microscope
- C. It is transparent
- D. The solute does not settle down on standing
Answer: B. The solute particles are visible under a microscope
Solutions are homogeneous mixtures where solute particles are molecular or ionic in size and invisible under a microscope, unlike suspensions or colloids.
Solutions are homogeneous mixtures where solute particles are molecular or ionic in size and invisible under a microscope, unlike suspensions or colloids.
Which of the following represents the correct definition of molarity?
- A. Number of moles of solute per 1000 g of solvent
- B. Number of moles of solute per litre of solution
- C. Number of grams of solute per 100 mL of solution
- D. Number of moles of solute per kilogram of solvent
Answer: B. Number of moles of solute per litre of solution
Molarity (M) is defined as the number of moles of solute dissolved per litre of the solution.
Molarity (M) is defined as the number of moles of solute dissolved per litre of the solution.
A 0.1 M solution of NaCl in water has a molality approximately equal to:
- A. 0.05 m
- B. 0.1 m
- C. 0.15 m
- D. 0.2 m
Answer: B. 0.1 m
For dilute aqueous solutions, molarity and molality are approximately equal since 1 litre of solution ≈ 1000 g of solvent.
For dilute aqueous solutions, molarity and molality are approximately equal since 1 litre of solution ≈ 1000 g of solvent.
Which of the following statements about mole fraction is correct?
- A. Mole fraction can be greater than 1
- B. Mole fraction is dimensionless
- C. Mole fraction is temperature-dependent
- D. The sum of mole fractions of all components in a solution is always 0.5
Answer: B. Mole fraction is dimensionless
Mole fraction is a dimensionless quantity, ranging from 0 to 1, and the sum of mole fractions of all components equals 1.
Mole fraction is a dimensionless quantity, ranging from 0 to 1, and the sum of mole fractions of all components equals 1.
Which of the following represents the correct expression for the elevation in boiling point, considering the van't Hoff factor for electrolytes?
- A. ΔTb = Kb × m
- B. ΔTb = Kb × i × m
- C. ΔTb = Kb/m
- D. ΔTb = Kb × m²
Answer: B. ΔTb = Kb × i × m
For electrolytes, the boiling point elevation is ΔTb = Kb × i × m, where i is the van't Hoff factor accounting for dissociation.
For electrolytes, the boiling point elevation is ΔTb = Kb × i × m, where i is the van't Hoff factor accounting for dissociation.