IMFs MCQs PDF

1. Which type of intermolecular force acts between all molecules, regardless of their polarity? a) Hydrogen bonds b) Permanent dipole-dipole forces c) Induced dipole forces (Van der Waals) d) Covalent bonds Answer: c) Induced dipole forces (Van der Waals) *Explanation: Induced dipole forces act bet...

1. Which type of intermolecular force acts between all molecules, regardless of their polarity? a) Hydrogen bonds b) Permanent dipole-dipole forces c) Induced dipole forces (Van der Waals) d) Covalent bonds Answer: c) Induced dipole forces (Van der Waals) *Explanation: Induced dipole forces act between all molecules because they can cause temporary dipoles even in non-polar molecules.* 2. Which molecule exhibits hydrogen bonding? a) CH₄ b) H₂O c) CO₂ d) CCl₄ Answer: b) H₂O *Explanation: Hydrogen bonding occurs when a hydrogen atom is directly bonded to a highly electronegative atom like oxygen, seen in water molecules.* 3. What intermolecular force is the strongest? a) Induced dipole forces b) Permanent dipole forces c) Covalent bonding d) Hydrogen bonding Answer: d) Hydrogen bonding *Explanation: Hydrogen bonds are the strongest type of intermolecular force due to the high electronegativity di erence and direct bonding with hydrogen.* 4. Among the halogens F₂, Cl₂, Br₂, and I₂, which shows the strongest induced dipole force? a) F₂ b) Cl₂ c) Br₂ d) I₂ Answer: d) I₂ *Explanation: I₂ has more electrons compared to the other halogens, resulting in stronger induced dipole forces or Van der Waals forces.* 5. Which type of intermolecular force is present in non-polar molecules but absent in polar molecules? a) Permanent dipole-dipole forces b) Hydrogen bonding c) Induced dipole forces d) Ionic bonding Answer: c) Induced dipole forces *Explanation: Induced dipole forces are present in all molecules, including non-polar ones, as the weakest form of IMF. They are not speci c to polar molecules.* 6. What causes permanent dipole-dipole forces? a) Temporary shifts in electron density b) Equal sharing of electrons c) Permanent unequal sharing of electrons d) Covalent bonding Answer: c) Permanent unequal sharing of electrons ff fi *Explanation: Permanent dipole-dipole forces result from permanent di erences in electronegativity between bonded atoms, creating partial charges that attract each other.* 7. Why does NH₃ have a higher boiling point than PH₃? a) NH₃ forms hydrogen bonds, while PH₃ does not b) PH₃ forms stronger dipole-dipole interactions c) PH₃ is held by ionic bonds d) NH₃ is heavier Answer: a) NH₃ forms hydrogen bonds, while PH₃ does not *Explanation: NH₃ forms hydrogen bonds due to N-H bonds, which are stronger than the van der Waals forces present in PH₃.* 8. Which molecule does not have permanent dipole-dipole forces? a) HCl b) CO₂ c) H₂O d) CH₃Cl Answer: b) CO₂ *Explanation: CO₂ is a linear molecule with polar bonds but overall non-polar structure due to symmetrical shape, hence it does not have permanent dipole forces.* 9. Which of these molecules has only induced dipole-dipole forces? a) H₂O b) HF c) CH₄ d) H₂S Answer: c) CH₄ *Explanation: CH₄ is a non-polar molecule, thus only has induced dipole-dipole forces (London dispersion forces).* 10. What is the main intermolecular force in solid iodine (I₂)? a) Hydrogen bonding b) Permanent dipole forces c) Covalent bonding d) Induced dipole forces Answer: d) Induced dipole forces *Explanation: Solid iodine is held together by induced dipole forces due to temporary dipoles created within iodine molecules.* 11. Which intermolecular force is responsible for the low density of ice compared to liquid water? a) Dipole-dipole interactions b) Hydrogen bonding c) Ionic bonding d) Van der Waals forces Answer: b) Hydrogen bonding *Explanation: Hydrogen bonding in ice forms a hexagonal structure with more space between molecules, making ice less dense than liquid water.* 12. What type of intermolecular force exists between molecules of methane (CH₄)? a) Hydrogen bonds b) Permanent dipole-dipole forces c) Induced dipole-dipole forces d) Ionic bonds Answer: c) Induced dipole-dipole forces ff  *Explanation: Methane is non-polar and thus its intermolecular forces are induced dipole-dipole forces (Van der Waals).* 13. Identify the dominant intermolecular force in hydrogen chloride (HCl). a) Induced dipole forces b) Permanent dipole-dipole forces c) Hydrogen bonding d) Metallic bonding Answer: b) Permanent dipole-dipole forces *Explanation: HCl is a polar molecule with a permanent dipole due to its electronegativity di erence between hydrogen and chlorine.* 14. Which substance demonstrates only London dispersion forces? a) NH₃ b) H₂O c) CO₂ d) HF Answer: c) CO₂ *Explanation: CO₂ is non-polar and symmetrical, leading to only London dispersion (induced dipole) forces.* 15. Which of the following pairs of molecules would most likely form hydrogen bonds with each other? a) H₂ and O₂ b) N₂ and CH₄ c) NH₃ and H₂O d) CO₂ and CF₄ Answer: c) NH₃ and H₂O *Explanation: Both molecules have hydrogen atoms directly connected to highly electronegative atoms (N and O), enabling hydrogen bonding.* 16. Which compound among the halogen halides (HX) exhibits the strongest intermolecular forces? a) HCl b) HF c) HBr d) HI Answer: b) HF *Explanation: HF exhibits hydrogen bonding, making it signi cantly stronger than the dipole forces in the other halogen halides.* 17. What is a characteristic of substances with permanent dipole-dipole interactions? a) Always insoluble in water b) High melting and boiling points compared to non-polar substances of similar size c) Conduct electricity in solid state d) Always non-polar Answer: b) High melting and boiling points compared to non-polar substances of similar size *Explanation: Permanent dipole-dipole interactions are stronger than induced dipoles, leading to higher melting and boiling points.* 18. What intermolecular force plays a key role in the solubility of ethanol in water? a) Van der Waals forces b) Ionic bonding c) Permanent dipole-dipole forces d) Hydrogen bonding ff fi Answer: d) Hydrogen bonding *Explanation: Ethanol and water can form hydrogen bonds with each other, aiding in ethanol's solubility in water.* 19. What intermolecular force exists between molecules of carbon tetrachloride (CCl₄)? a) Hydrogen bonding b) Permanent dipole-dipole forces c) Induced dipole-dipole forces d) Ionic bonds Answer: c) Induced dipole-dipole forces *Explanation: CCl₄ is a non-polar molecule despite its polar bonds due to symmetry, leading to induced dipole forces only.* 20. Which intermolecular force is responsible for the anomalously high boiling point of water? a) Induced dipole forces b) Permanent dipole-dipole forces c) Hydrogen bonding d) Ionic bonding Answer: c) Hydrogen bonding *Explanation: Water's high boiling point is due to its strong hydrogen bonds between water molecules.* 21. Which of these molecules would experience the strongest van der Waals (induced dipole) forces? a) He b) Ne c) Ar d) Kr Answer: d) Kr *Explanation: Krypton has the most electrons among these noble gases, leading to stronger induced dipole forces.* 22. What type of intermolecular force is present in CH₃F? a) Induced dipole-dipole forces b) Permanent dipole-dipole forces c) Hydrogen bonding d) Ionic bonding Answer: b) Permanent dipole-dipole forces *Explanation: CH₃F is a polar molecule due to the C-F bond, leading to permanent dipole-dipole forces.* 23. What intermolecular force would be absent in a sample of SiF₄? a) Induced dipole-dipole forces b) Permanent dipole-dipole forces c) London dispersion forces d) Van der Waals forces Answer: b) Permanent dipole-dipole forces *Explanation: SiF₄ is non-polar and symmetrical, thus lacking permanent dipole-dipole forces.* 25. What determines the strength of London dispersion forces? a) Polarity of the molecules b) Number of hydrogen bonds present c) Surface area and number of electrons in the molecule d) Number of lone pairs Answer: c) Surface area and number of electrons in the molecule *Explanation: The more electrons and larger surface area a molecule has, the stronger its London dispersion forces due to greater induced dipole interaction.* 26. Which type of intermolecular force does not rely on the presence of dipoles (either temporary or permanent)? a) Hydrogen bonding b) Permanent dipole-dipole forces c) London dispersion forces d) Ionic bonding Answer: d) Ionic bonding *Explanation: Ionic bonding involves electrostatic attractions between ions, independent of temporary or permanent dipoles.* 27. Why does uorine (F₂) have a lower boiling point than iodine (I₂)? a) Less polarizable electron cloud b) Stronger induced dipole forces c) Hydrogen bonding d) Permanent dipole-dipole interaction Answer: a) Less polarizable electron cloud *Explanation: Fluorine has fewer electrons and a smaller electron cloud than iodine, resulting in weaker London dispersion forces with a lower boiling point.* 28. Which molecule exhibits the strongest type of intermolecular force? a) HBr b) HF c) HCl d) H₂ Answer: b) HF *Explanation: HF demonstrates hydrogen bonding, the strongest intermolecular force among the given options.* 29. Which molecule does not exhibit hydrogen bonding? a) HF b) NH₃ c) H₂O d) CH₄ Answer: d) CH₄ *Explanation: CH₄ does not have any hydrogen atoms bonded to highly electronegative atoms like N, O, or F, thus it cannot form hydrogen bonds.* 30. What intermolecular force explains the solubility of non-polar molecules in non-polar solvents? a) Hydrogen bonds b) Permanent dipole-dipole forces c) Ionic bonding d) London dispersion forces Answer: d) London dispersion forces *Explanation: Non-polar molecules dissolve in non-polar solvents because they interact through London dispersion forces (induced dipole forces).* fl