CHEM134 C002: COLLIGATIVE PROPERTIES
EXAM Spring 2026 – Digital Beyond Labz
Format GRADED A+
Course: CHEM134 – General Chemistry with Qualitative Analysis
Section: C002
Semester: Spring 2026
Exam Title: Digital Colligative Properties – Beyond Labz Assessment
Total Questions: 50
Total Points: 100
Time Allowed: 75 minutes
Instructions:
• Answer all questions in the space provided.
• Show all calculations for partial credit.
• Use the Van't Hoff factor (i) for electrolytes: NaCl (i=2), CaCl₂ (i=3), AlCl₃ (i=4), glucose
(i=1), sucrose (i=1).
• Constants: Kf (water) = 1.86 °C·kg/mol, Kb (water) = 0.512 °C·kg/mol, R = 0.0821
L·atm/(mol·K)
SECTION A: MULTIPLE CHOICE (Questions 1–20)
Each question is worth 2 points. Circle the best answer.
Question 1
Which of the following is a colligative property?
A) Density
B) Viscosity
C) Freezing point depression
D) Color
, Answer: C) Freezing point depression
Rationale: Colligative properties depend only on the number of solute particles, not their
identity. Freezing point depression, boiling point elevation, vapor pressure lowering, and
osmotic pressure are the four colligative properties.
Question 2
A solution contains a non-volatile solute. Compared to the pure solvent, the vapor pressure of
the solution is:
A) Higher
B) Lower
C) The same
D) Unpredictable
Answer: B) Lower
Rationale: Raoult's Law states that the vapor pressure of a solution equals the mole fraction of
the solvent multiplied by the vapor pressure of the pure solvent. Adding a non-volatile solute
lowers the mole fraction of the solvent, thus lowering vapor pressure.
Question 3
What is the Van't Hoff factor (i) for NaCl in water?
A) 1
B) 2
C) 3
D) 4
Answer: B) 2
Rationale: NaCl dissociates completely into Na⁺ and Cl⁻ ions, producing two particles per
formula unit. Therefore i = 2.
Question 4
Which solution would have the highest boiling point?
A) 0.1 m glucose
B) 0.1 m NaCl
, C) 0.1 m CaCl₂
D) 0.1 m AlCl₃
Answer: D) 0.1 m AlCl₃
Rationale: ΔTb = i × Kb × m. AlCl₃ dissociates into Al³⁺ + 3Cl⁻ (i = 4), which is the highest i value
among the options, producing the greatest boiling point elevation.
Question 5
The freezing point of a 1.0 m NaCl solution is approximately:
A) 0°C
B) -1.86°C
C) -3.72°C
D) -5.58°C
Answer: C) -3.72°C
Rationale: ΔTf = i × Kf × m = 2 × 1.86 × 1.0 = 3.72°C. Since freezing point is lowered, the solution
freezes at -3.72°C.
Question 6
Which of the following is NOT required to calculate boiling point elevation?
A) Kb of the solvent
B) Molar mass of the solute
C) Molality of the solution
D) Van't Hoff factor
Answer: B) Molar mass of the solute
Rationale: ΔTb = i × Kb × m. Molality (m) requires moles of solute, which comes from mass and
molar mass. However, if molality is already given, molar mass is not directly needed.
Question 7
Osmotic pressure (Π) is calculated using which equation?
A) Π = iMRT
B) Π = iKfm
C) Π = iKbm
D) Π = mRT
EXAM Spring 2026 – Digital Beyond Labz
Format GRADED A+
Course: CHEM134 – General Chemistry with Qualitative Analysis
Section: C002
Semester: Spring 2026
Exam Title: Digital Colligative Properties – Beyond Labz Assessment
Total Questions: 50
Total Points: 100
Time Allowed: 75 minutes
Instructions:
• Answer all questions in the space provided.
• Show all calculations for partial credit.
• Use the Van't Hoff factor (i) for electrolytes: NaCl (i=2), CaCl₂ (i=3), AlCl₃ (i=4), glucose
(i=1), sucrose (i=1).
• Constants: Kf (water) = 1.86 °C·kg/mol, Kb (water) = 0.512 °C·kg/mol, R = 0.0821
L·atm/(mol·K)
SECTION A: MULTIPLE CHOICE (Questions 1–20)
Each question is worth 2 points. Circle the best answer.
Question 1
Which of the following is a colligative property?
A) Density
B) Viscosity
C) Freezing point depression
D) Color
, Answer: C) Freezing point depression
Rationale: Colligative properties depend only on the number of solute particles, not their
identity. Freezing point depression, boiling point elevation, vapor pressure lowering, and
osmotic pressure are the four colligative properties.
Question 2
A solution contains a non-volatile solute. Compared to the pure solvent, the vapor pressure of
the solution is:
A) Higher
B) Lower
C) The same
D) Unpredictable
Answer: B) Lower
Rationale: Raoult's Law states that the vapor pressure of a solution equals the mole fraction of
the solvent multiplied by the vapor pressure of the pure solvent. Adding a non-volatile solute
lowers the mole fraction of the solvent, thus lowering vapor pressure.
Question 3
What is the Van't Hoff factor (i) for NaCl in water?
A) 1
B) 2
C) 3
D) 4
Answer: B) 2
Rationale: NaCl dissociates completely into Na⁺ and Cl⁻ ions, producing two particles per
formula unit. Therefore i = 2.
Question 4
Which solution would have the highest boiling point?
A) 0.1 m glucose
B) 0.1 m NaCl
, C) 0.1 m CaCl₂
D) 0.1 m AlCl₃
Answer: D) 0.1 m AlCl₃
Rationale: ΔTb = i × Kb × m. AlCl₃ dissociates into Al³⁺ + 3Cl⁻ (i = 4), which is the highest i value
among the options, producing the greatest boiling point elevation.
Question 5
The freezing point of a 1.0 m NaCl solution is approximately:
A) 0°C
B) -1.86°C
C) -3.72°C
D) -5.58°C
Answer: C) -3.72°C
Rationale: ΔTf = i × Kf × m = 2 × 1.86 × 1.0 = 3.72°C. Since freezing point is lowered, the solution
freezes at -3.72°C.
Question 6
Which of the following is NOT required to calculate boiling point elevation?
A) Kb of the solvent
B) Molar mass of the solute
C) Molality of the solution
D) Van't Hoff factor
Answer: B) Molar mass of the solute
Rationale: ΔTb = i × Kb × m. Molality (m) requires moles of solute, which comes from mass and
molar mass. However, if molality is already given, molar mass is not directly needed.
Question 7
Osmotic pressure (Π) is calculated using which equation?
A) Π = iMRT
B) Π = iKfm
C) Π = iKbm
D) Π = mRT
