UNE GENERAL CHEMISTRY II
MIDTERM (1-7 WEEKS)
COMPREHESIVE ACTUAL
QUESTIONS AND 100 % VERIFIED
ANSWERS |LATEST 2026/2027
UPDATE , GUARANTEED PASS
INTERMOLECULAR FORCES & PHASE CHANGES (Questions 1–80)
1. Which intermolecular force is primarily responsible for the relatively high boiling point of water?
A) London dispersion forces
B) Dipole-dipole forces
C) Hydrogen bonding
D) Ion-dipole forces
Correct Answer: C
Hydrogen bonding is the strongest type of dipole-dipole interaction and requires significant energy to overcome,
resulting in a higher boiling point.
2. Which of the following molecules exhibits hydrogen bonding?
A) CH₄
B) H₂S
C) HF
D) HCl
Correct Answer: C
Hydrogen bonding occurs when hydrogen is bonded to highly electronegative atoms: F, O, or N. HF has hydrogen
bonded to fluorine.
3. Which substance would have the highest vapor pressure at 25°C?
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,A) Water (H₂O)
B) Methanol (CH₃OH)
C) Diethyl ether (CH₃CH₂OCH₂CH₃)
D) Ethylene glycol (HOCH₂CH₂OH)
Correct Answer: C
Diethyl ether has the weakest intermolecular forces (only dispersion and weak dipole-dipole), so its molecules
escape most readily, giving the highest vapor pressure.
4. Which of the following correctly ranks the boiling points of these compounds from lowest to highest?
A) CH₄ < NH₃ < H₂O
B) NH₃ < CH₄ < H₂O
C) H₂O < NH₃ < CH₄
D) CH₄ < H₂O < NH₃
Correct Answer: A
CH₄ has only dispersion forces (lowest BP). NH₃ has hydrogen bonding but weaker than H₂O because oxygen is
more electronegative than nitrogen. H₂O has the strongest hydrogen bonding (highest BP).
5. Which type of intermolecular force is present in all molecules?
A) Hydrogen bonding
B) Dipole-dipole forces
C) London dispersion forces
D) Ion-dipole forces
Correct Answer: C
London dispersion forces arise from temporary fluctuations in electron distribution and are present in all molecules,
regardless of polarity.
6. Which substance would have the strongest London dispersion forces?
A) CH₄
B) C₃H₈
C) C₆H₁₄
D) C₁₀H₂₂
Correct Answer: D
Larger molecules with more electrons have stronger dispersion forces. C₁₀H₂₂ is the largest molecule listed.
7. Which of the following phase changes is exothermic?
A) Sublimation
B) Vaporization
C) Fusion
D) Deposition
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,Correct Answer: D
Deposition (gas to solid) releases energy, making it exothermic. Sublimation, vaporization, and fusion all require
energy input (endothermic).
8. What is the heat required to convert 50.0 g of ice at 0°C to liquid water at 0°C?
(ΔHfus = 6.01 kJ/mol)
A) 16.7 kJ
B) 10.0 kJ
C) 33.4 kJ
D) 50.0 kJ
Correct Answer: A
Moles of ice = 50.0 g / 18.02 g/mol = 2.77 mol. Heat = 2.77 mol × 6.01 kJ/mol = 16.7 kJ.
9. Which of the following statements about vapor pressure is correct?
A) Vapor pressure increases with increasing temperature
B) Vapor pressure decreases with increasing temperature
C) Vapor pressure is independent of temperature
D) Vapor pressure is inversely proportional to temperature
Correct Answer: A
As temperature increases, more molecules have sufficient kinetic energy to overcome intermolecular forces and
enter the gas phase, increasing vapor pressure.
10. At the boiling point of a liquid:
A) Vapor pressure equals atmospheric pressure
B) Vapor pressure is zero
C) Vapor pressure is at its maximum
D) The liquid and solid phases are in equilibrium
Correct Answer: A
Boiling occurs when the vapor pressure of the liquid equals the external (atmospheric) pressure.
11. Which substance would have the lowest freezing point if dissolved in water?
A) 0.1 m NaCl
B) 0.1 m CaCl₂
C) 0.1 m Glucose (C₆H₁₂O₆)
D) 0.1 m AlCl₃
Correct Answer: D
AlCl₃ dissociates into 4 particles (Al³⁺ + 3Cl⁻), giving the greatest freezing point depression (ΔTf = i × Kf × m).
12. Which of the following is an example of a dipole-dipole interaction?
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, A) The attraction between Na⁺ and Cl⁻ ions
B) The attraction between two HCl molecules
C) The attraction between two He atoms
D) The attraction between H₂O and Na⁺
Correct Answer: B
Dipole-dipole forces occur between polar molecules. HCl is polar with a permanent dipole.
13. Which molecule has the strongest intermolecular forces?
A) CH₃CH₃
B) CH₃OH
C) CH₃F
D) CH₃Cl
Correct Answer: B
CH₃OH exhibits hydrogen bonding (O–H bond), which is stronger than the dipole-dipole forces in CH₃F and CH₃Cl
and the dispersion forces in CH₃CH₃.
14. What is the predominant intermolecular force in liquid CCl₄?
A) Hydrogen bonding
B) Dipole-dipole forces
C) London dispersion forces
D) Ion-dipole forces
Correct Answer: C
CCl₄ is a nonpolar molecule; the only intermolecular force present is London dispersion forces.
15. Which of the following would have the highest boiling point?
A) He
B) Ne
C) Ar
D) Kr
Correct Answer: D
As atomic size increases down Group 18, the number of electrons increases, leading to stronger dispersion forces
and higher boiling points.
16. Vapor pressure is measured when:
A) The rate of evaporation equals the rate of condensation
B) The rate of evaporation is greater than the rate of condensation
C) The rate of condensation is greater than the rate of evaporation
D) No molecules are in the gas phase
Correct Answer: A
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid (or solid) phase.
4|Page SUCCESS!!!
MIDTERM (1-7 WEEKS)
COMPREHESIVE ACTUAL
QUESTIONS AND 100 % VERIFIED
ANSWERS |LATEST 2026/2027
UPDATE , GUARANTEED PASS
INTERMOLECULAR FORCES & PHASE CHANGES (Questions 1–80)
1. Which intermolecular force is primarily responsible for the relatively high boiling point of water?
A) London dispersion forces
B) Dipole-dipole forces
C) Hydrogen bonding
D) Ion-dipole forces
Correct Answer: C
Hydrogen bonding is the strongest type of dipole-dipole interaction and requires significant energy to overcome,
resulting in a higher boiling point.
2. Which of the following molecules exhibits hydrogen bonding?
A) CH₄
B) H₂S
C) HF
D) HCl
Correct Answer: C
Hydrogen bonding occurs when hydrogen is bonded to highly electronegative atoms: F, O, or N. HF has hydrogen
bonded to fluorine.
3. Which substance would have the highest vapor pressure at 25°C?
1|Page SUCCESS!!!
,A) Water (H₂O)
B) Methanol (CH₃OH)
C) Diethyl ether (CH₃CH₂OCH₂CH₃)
D) Ethylene glycol (HOCH₂CH₂OH)
Correct Answer: C
Diethyl ether has the weakest intermolecular forces (only dispersion and weak dipole-dipole), so its molecules
escape most readily, giving the highest vapor pressure.
4. Which of the following correctly ranks the boiling points of these compounds from lowest to highest?
A) CH₄ < NH₃ < H₂O
B) NH₃ < CH₄ < H₂O
C) H₂O < NH₃ < CH₄
D) CH₄ < H₂O < NH₃
Correct Answer: A
CH₄ has only dispersion forces (lowest BP). NH₃ has hydrogen bonding but weaker than H₂O because oxygen is
more electronegative than nitrogen. H₂O has the strongest hydrogen bonding (highest BP).
5. Which type of intermolecular force is present in all molecules?
A) Hydrogen bonding
B) Dipole-dipole forces
C) London dispersion forces
D) Ion-dipole forces
Correct Answer: C
London dispersion forces arise from temporary fluctuations in electron distribution and are present in all molecules,
regardless of polarity.
6. Which substance would have the strongest London dispersion forces?
A) CH₄
B) C₃H₈
C) C₆H₁₄
D) C₁₀H₂₂
Correct Answer: D
Larger molecules with more electrons have stronger dispersion forces. C₁₀H₂₂ is the largest molecule listed.
7. Which of the following phase changes is exothermic?
A) Sublimation
B) Vaporization
C) Fusion
D) Deposition
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,Correct Answer: D
Deposition (gas to solid) releases energy, making it exothermic. Sublimation, vaporization, and fusion all require
energy input (endothermic).
8. What is the heat required to convert 50.0 g of ice at 0°C to liquid water at 0°C?
(ΔHfus = 6.01 kJ/mol)
A) 16.7 kJ
B) 10.0 kJ
C) 33.4 kJ
D) 50.0 kJ
Correct Answer: A
Moles of ice = 50.0 g / 18.02 g/mol = 2.77 mol. Heat = 2.77 mol × 6.01 kJ/mol = 16.7 kJ.
9. Which of the following statements about vapor pressure is correct?
A) Vapor pressure increases with increasing temperature
B) Vapor pressure decreases with increasing temperature
C) Vapor pressure is independent of temperature
D) Vapor pressure is inversely proportional to temperature
Correct Answer: A
As temperature increases, more molecules have sufficient kinetic energy to overcome intermolecular forces and
enter the gas phase, increasing vapor pressure.
10. At the boiling point of a liquid:
A) Vapor pressure equals atmospheric pressure
B) Vapor pressure is zero
C) Vapor pressure is at its maximum
D) The liquid and solid phases are in equilibrium
Correct Answer: A
Boiling occurs when the vapor pressure of the liquid equals the external (atmospheric) pressure.
11. Which substance would have the lowest freezing point if dissolved in water?
A) 0.1 m NaCl
B) 0.1 m CaCl₂
C) 0.1 m Glucose (C₆H₁₂O₆)
D) 0.1 m AlCl₃
Correct Answer: D
AlCl₃ dissociates into 4 particles (Al³⁺ + 3Cl⁻), giving the greatest freezing point depression (ΔTf = i × Kf × m).
12. Which of the following is an example of a dipole-dipole interaction?
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, A) The attraction between Na⁺ and Cl⁻ ions
B) The attraction between two HCl molecules
C) The attraction between two He atoms
D) The attraction between H₂O and Na⁺
Correct Answer: B
Dipole-dipole forces occur between polar molecules. HCl is polar with a permanent dipole.
13. Which molecule has the strongest intermolecular forces?
A) CH₃CH₃
B) CH₃OH
C) CH₃F
D) CH₃Cl
Correct Answer: B
CH₃OH exhibits hydrogen bonding (O–H bond), which is stronger than the dipole-dipole forces in CH₃F and CH₃Cl
and the dispersion forces in CH₃CH₃.
14. What is the predominant intermolecular force in liquid CCl₄?
A) Hydrogen bonding
B) Dipole-dipole forces
C) London dispersion forces
D) Ion-dipole forces
Correct Answer: C
CCl₄ is a nonpolar molecule; the only intermolecular force present is London dispersion forces.
15. Which of the following would have the highest boiling point?
A) He
B) Ne
C) Ar
D) Kr
Correct Answer: D
As atomic size increases down Group 18, the number of electrons increases, leading to stronger dispersion forces
and higher boiling points.
16. Vapor pressure is measured when:
A) The rate of evaporation equals the rate of condensation
B) The rate of evaporation is greater than the rate of condensation
C) The rate of condensation is greater than the rate of evaporation
D) No molecules are in the gas phase
Correct Answer: A
Vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid (or solid) phase.
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