Intermolecular forces: Edexcel International A Level Chemistry questions

Every Edexcel International A Level Chemistry exam question on Intermolecular forces (specification points 7.1–7.6), 2019–2025, with its mark scheme and examiner’s report.

All 89 questions on Intermolecular forces, as a list

June 2025, AS Unit 1, Q23(b)(v) (2 marks): Ethene and poly(ethene) have different melting temperatures. Molecule Melting temperature (K) ethene 104.1 poly(ethene) 400 Explain why their melting temperatur
June 2025, AS Unit 2, Q3 (1 mark): Which amine, with molecular formula C3H9N , has the lowest boiling temperature? A (CH3)3N B CH3CH2NHCH3 C CH3CH2CH2NH2 D CH3CH(NH2)CH3
June 2025, AS Unit 2, Q14(b)(i) (4 marks): Explain the differences in the boiling temperatures of the Group 5 hydrides shown. Detailed descriptions of the intermolecular forces are not required. Hydride
June 2025, Unit 4, Q15(b) (3 marks): Butanoic acid is very soluble in water. This is due to strong intermolecular forces between butanoic acid molecules and water molecules. Complete the diagram by
June 2025, Unit 5, Q17(a)(iii) (2 marks): Trimethylamine is a gas at room temperature but readily dissolves in water. Draw a diagram of the intermolecular force that leads to trimethylamine being solubl
January 2025, AS Unit 1, Q10 (1 mark): Sulfur has a higher melting temperature than white phosphorus, P4. Which is a possible reason for this? A sulfur molecules have a greater permanent dipole than
January 2025, AS Unit 2, Q7(a) (1 mark): Which is the best estimate for the boiling temperature of HBr? (1) A 59°C B –20°C C –67°C D –90°C
January 2025, AS Unit 2, Q7(b) (1 mark): Why does HF not fit the pattern of the boiling temperatures of the other hydrogen halides? (1) A it forms hydrogen bonds B it is much smaller than the other hyd
January 2025, AS Unit 2, Q18(a) (3 marks): Draw a diagram to show hydrogen bonding between two H2O molecules in ice. Include bond angles and relevant dipoles and lone pairs in your answer. (3)
January 2025, AS Unit 2, Q18(b) (3 marks): Compare and contrast the effect of intermolecular forces on the properties of water and ammonia, using the data shown. (3) Boiling temperature Density at 223 K
January 2025, Unit 4, Q16(a) (2 marks): Explain why pentan-2-one has a lower boiling temperature than pentan‑2‑ol. (2)
October 2024, AS Unit 1, Q10(b) (1 mark): The melting temperatures of these elements are shown in the table. Element Na Mg Al Si P S Cl Melting temperature / K 371 922 933 1683 317 392 172 Which of the
October 2024, AS Unit 2, Q19(a)(i) (2 marks): Describe how London forces arise. (2)
October 2024, AS Unit 2, Q19(a)(ii) (1 mark): State why the London forces in hydrogen iodide are stronger than those in hydrogen chloride and hydrogen bromide. (1)
October 2024, AS Unit 2, Q19(a)(iii) (1 mark): The boiling temperature of hydrogen fluoride is +20 °C. State what causes hydrogen fluoride to have such an unusually high boiling temperature. (1)
October 2024, Unit 4, Q2 (1 mark): Which compound will have the highest boiling temperature? A CH3CH2CH2CH2CH3 B CH3CH2CH2CHO C CH3COCH2CH3 D CH3CH2COOH Use this space for any rough working. Anyt
October 2024, Unit 5, Q15(a) (2 marks): Butylamine is miscible with water. Draw a labelled diagram to show one of the intermolecular interactions between a butylamine molecule and a molecule of water.
June 2024, AS Unit 2, Q2 (1 mark): Sodium chloride dissolves in water to form a solution because of the interactions between the sodium chloride and water. What are these interactions? A dipole‑d
June 2024, AS Unit 2, Q4(a) (1 mark): Which isomer has the highest boiling temperature? (1) A B C D
June 2024, AS Unit 2, Q4(b) (1 mark): Which compound has the highest boiling temperature? (1) A pentane B cyclopentane C butan‑1‑ol D butane‑1,4‑diol
June 2024 (R), AS Unit 2, Q15 (1 mark): The compounds W, X, Y and Z have different boiling temperatures. CH3 CH3CH2CH2CH3 H3C C CH3 H Compound W Compound X CH3 H3C CH3 CH3CH2CH2CH2Br C Br Compound Y C
June 2024 (R), AS Unit 2, Q22(e) (6 marks): Both urea and ammonium nitrate are soluble in water. Discuss the differences in the interactions of water molecules with both urea and ammonium nitrate. Include
January 2024, AS Unit 2, Q1 (1 mark): Which compound has intermolecular hydrogen bonding? A HF B H2Te C AsH3 D SnH4
January 2024, AS Unit 2, Q2 (1 mark): In which process are intermolecular hydrogen bonds broken? A H2(g) → 2H(g) B H2O(l) → H2O(g) C H2(l) → H2(g) D H2(g) + ½O2(g) → H2O(g)
January 2024, AS Unit 2, Q3 (1 mark): A compound contains • molecules with non-polar bonds • permanent dipole-permanent dipole forces between its molecules. What could be the formula of this compoun
January 2024, AS Unit 2, Q4 (1 mark): Which alkane has the strongest London forces in the liquid phase? A (CH3)4C B CH3CH2CH2CH2CH3 C (C2H5)4C D CH3(CH2)7CH3
January 2024, AS Unit 2, Q5 (1 mark): In which liquid solvent would the solubility of lithium chloride (LiCl) be lowest? A ammonia B cyclohexane C methanol D water
January 2024, Unit 4, Q14 (1 mark): Which substance is the least soluble in water? A propanal B propan‑1‑ol C propanoic acid D sodium propanoate Use this space for any rough working. Anything you
October 2023, AS Unit 2, Q4 (1 mark): Which row in the table shows the forces between the molecules in the liquid state? Permanent dipole‑dipole Molecule London forces Hydrogen bonding interaction A
October 2023, AS Unit 2, Q5 (1 mark): Which of these isoelectronic compounds would be expected to have the highest boiling temperature? A butan‑1‑ol B 2‑methylpropan‑1‑ol C 2‑methylpropan‑2‑ol D pen
October 2023, AS Unit 2, Q19(d) (6 marks): Explain why iodine is more soluble in hexane than in water, by considering the intermolecular forces in iodine, hexane and water and any intermolecular forces f
June 2023, AS Unit 2, Q4 (1 mark): Which of these alkanes would be expected to have the highest boiling temperature? A B C D
June 2023, AS Unit 2, Q5 (1 mark): The boiling temperature of hexane is 69 °C and that of cyclohexane is 81 °C. The main reason that cyclohexane has a higher boiling temperature is that cyclohexa
June 2023, AS Unit 2, Q6 (1 mark): The structures and boiling temperatures of butane and propanal are shown. Butane Propanal O CH2 CH3 C CH2 CH3 CH3 CH2 H Tb = 0 °C Tb = 49 °C The main reason tha
June 2023, AS Unit 2, Q7 (1 mark): Hydrogen bonds are formed when methanol dissolves in water. Which structure best represents a hydrogen bond between methanol and water? H H O : A H C H O H H H
June 2023, AS Unit 2, Q20(b) (6 marks): Two alternatives to hydrocarbon fuels are hydrogen and ammonia. Hydrogen burns to form water as the only product but hydrogen is extremely hard to liquefy. Ammo
June 2023, AS Unit 2, Q22(c)(iii) (2 marks): Commercial disinfectants are often made more viscous by adding propane‑1,2,3‑triol to the aqueous solution. Suggest how propane-1,2,3-triol makes disinfectants
June 2023, Unit 4, Q10 (1 mark): How do the boiling temperature and the solubility in water of butanoic acid compare with the values for hexane? Boiling temperature Solubility in water A lower
June 2023, Unit 5, Q24(a)(ii) (3 marks): Explain why PAM is able to absorb large amounts of water. Include a diagram in your answer. (3)
January 2023, AS Unit 2, Q4 (1 mark): Which compound has London forces as the only intermolecular force? A HF B OF2 C PF3 D CF4 Use this space for any rough working. Anything you write in this space
January 2023, AS Unit 2, Q5 (1 mark): Which compound has intermolecular hydrogen bonding? A (CH3)3N B (CH3)3CF C (CH3)3COH D (CH3)3CCHO
January 2023, AS Unit 2, Q6 (1 mark): Which sequence shows the hydrogen halides in order of decreasing boiling temperature? A HF > HCl > HBr > HI B HF > HI > HBr > HCl C HI > HF > HCl > HBr D HI > H
January 2023, AS Unit 2, Q19(b)(ii) (2 marks): Explain why alcohol B has a higher boiling temperature than alcohol A. (2)
January 2023, AS Unit 2, Q19(b)(iii) (3 marks): Explain why alcohol B is completely soluble in ethanol but only slightly soluble in water. A detailed description of the forces involved is not required. (3)
January 2023, Unit 4, Q13 (1 mark): Propanal has a much higher boiling temperature than butane even though both compounds have the same molar mass. The main reason for the difference in boiling te
October 2022, AS Unit 2, Q9 (1 mark): Why is the boiling temperature of hydrogen iodide higher than that of hydrogen bromide? A hydrogen iodide has stronger London forces than hydrogen bromide B hyd
October 2022, AS Unit 2, Q11 (1 mark): Which compound has the highest boiling temperature? OH A OH B C D Use this space for any rough working. Anything you write in this space will gain no credit.
October 2022, AS Unit 2, Q12 (1 mark): Which compound does not form hydrogen bonds between its molecules? A HCl B H2O C HF D NH3
October 2022, AS Unit 2, Q21(a)(i) (2 marks): At room temperature and pressure, sulfur is a solid and oxygen a gas. Explain why sulfur and oxygen exist in different states by referring to the intermolecular
October 2022, Unit 4, Q11 (1 mark): Which compound is both completely miscible in water and has a higher boiling temperature than water? A CH3COOH B CH3COCH3 C CH3CH2CH2CHO D CH3CH2COOCH2CH3
June 2022, AS Unit 2, Q3 (1 mark): Which of these compounds would be expected to have the highest boiling temperature? A (CH3)3COH B CH3CH2CH2CH2OH C CH3CH2CH(CH3)2 D CH3CH2CH2CH2CH3 Use this spa
June 2022, AS Unit 2, Q16(d) (4 marks): The graph shows the boiling temperatures of the hydrogen halides. 350 300 250 200 Boiling temperature / K 150 100 50 0 HI HF HCl HBr Explain the trend in the bo
January 2022, AS Unit 2, Q5 (1 mark): Which sequence shows the molecules in order of increasing boiling temperature? A H2O < Br2 < Cl2 < CH4 B Br2 < CH4 < Cl2 < H2O C Cl2 < CH4 < H2O < Br2 D CH4 < C
January 2022, AS Unit 2, Q6 (1 mark): Which is not correct about ice? A ice has a lower density than water B H2O molecules are further apart in ice than in water C the H−O−H bond angle is the same i
January 2022, AS Unit 2, Q7 (1 mark): Which intermolecular forces exist between the molecules of the compound shown? HO O A hydrogen bonding and London forces only B hydrogen bonding and permanent d
January 2022, AS Unit 2, Q8(a) (1 mark): Which of these alkanes has the highest boiling temperature? (1) A butane B hexane C pentane D propane
January 2022, AS Unit 2, Q8(b) (1 mark): Which of these alkanes has the lowest boiling temperature? (1) A B C D
January 2022, AS Unit 2, Q9 (1 mark): Which solvent dissolves the greatest amount of hydrocarbon C35H72? A butan‑1‑ol B ethanoic acid C hexane D water Use this space for any rough working. Anything
January 2022, AS Unit 2, Q24(a) (3 marks): Urea has a melting temperature of 133 °C. Explain why this value is higher than expected for a relatively small molecule. (3)
January 2022, Unit 4, Q20(a)(iii) (3 marks): The solubility of hexanoic acid in water is 1.08 g per 100 g of water. The isomer of hexanoic acid, butyl ethanoate, CH3CO2C4H9, has a solubility of 0.68 g per
October 2021, AS Unit 2, Q6 (1 mark): Which of these isomers has the highest boiling temperature? A B C D Use this space for any rough working. Anything you write in this space will gain no credit.
October 2021, AS Unit 2, Q16 (1 mark): Which row shows the hydrogen halides in order of increasing boiling temperature? Lowest Highest HI A HF HCl HBr HI B HBr HCl HF HI C HCl HBr HF HI D HF HBr HCl
October 2021, AS Unit 2, Q20(c) (4 marks): The boiling temperatures of some halogenoalkanes are shown. Boiling temperature Halogenoalkane / °C 1-chloropropane 47 1-bromopropane 71 1-iodopropane 103 Expla
October 2021, AS Unit 2, Q22(d)(i) (1 mark): Give a possible reason why ethanol is able to absorb water. (1)
October 2021, Unit 4, Q11 (1 mark): Ethanal and propane have the same molar mass but ethanal has a much higher boiling temperature. Ethanal is fully miscible in water but propane is almost insolub
June 2021, AS Unit 2, Q20(a) (6 marks): Some data for three small molecules are shown. Boiling temperature Molecule Mr / °C Fluorine 38.0 −188 Hydrogen chloride 36.5 −85 Methanol 32.0 65 Explain the l
June 2021, AS Unit 2, Q20(b) (2 marks): Calcium chloride is soluble in water. Complete the diagram to show how water molecules interact with each ion. You may use to represent a water molecule. (2) Cl
June 2021, AS Unit 2, Q20(c) (2 marks): Explain why bromine is a liquid but iodine is a solid at room temperature. Detailed explanations of the forces involved are not required. (2)
June 2021, Unit 5, Q11 (1 mark): Hydrogen bonds are formed when methylamine dissolves in water. Which structure best represents a hydrogen bond between methylamine and water? H H O A H C N H H
January 2021, AS Unit 1, Q19(b)(i) (2 marks): Explain why PCl5 has a higher melting temperature than SbCl5 . (2)
January 2021, AS Unit 2, Q2 (1 mark): Which of these isomers with the formula C8H18 has the lowest boiling temperature? A CH3CH(CH3)CH2CH2CH(CH3)CH3 B CH3CH(CH3)CH2CH2CH2CH2CH3 C CH3C(CH3)2CH2CH(CH3
January 2021, AS Unit 2, Q3 (1 mark): Which of these pure compounds has hydrogen bonding in the liquid state? A 1,1,1-trichloroethane, CH3CCl3 B trimethylamine, (CH3)3N C hydrogen fluoride, HF D hyd
January 2021, AS Unit 2, Q5 (1 mark): The viscosities of four liquid organic compounds are compared by placing the liquids in separate identical tubes, each with an air bubble at the top. Air bubble
January 2021, AS Unit 2, Q19(b) (3 marks): The product of the reaction is a mixture of ethanol and water. Explain why ethanol and water mix together fully. You may find it helpful to draw a diagram. (3)
January 2021, AS Unit 2, Q20(b)(ii) (3 marks): Complete the diagrams to show how the ions formed in the reaction between DMAA and hydrochloric acid interact with water molecules. (3)
January 2021, AS Unit 3, Q4(a)(ii) (2 marks): Explain why the product in the organic layer in Step 2 does not mix with the aqueous layer. (2)
January 2021, Unit 4, Q19(d) (6 marks): Explain, in terms of all the intermolecular forces involved, why butanal has a higher boiling temperature than pentane but a lower boiling temperature than prop
October 2020, AS Unit 2, Q3 (1 mark): Which of the following statements about water is not due to hydrogen bonding? A water has a less open structure than ice B ice cubes float in a glass of iced wa
October 2020, AS Unit 2, Q4 (1 mark): The skeletal formulae of three isomers are shown. X Y Z Which series shows the correct order of increasing boiling temperatures? A Y, X, Z B X, Y, Z C Y, Z, X D
October 2020, AS Unit 2, Q13(b)(iii) (3 marks): Explain, with reference to their intermolecular forces, why the boiling temperatures of alkanes increase as the number of carbon atoms increases. A detailed des
October 2020, Unit 4, Q17(d) (3 marks): State which one of the isomers A, E and F has the highest boiling temperature. Justify your answer. (3)
January 2020, AS Unit 1, Q18(e) (2 marks): Chlorine is a gas at room temperature and pressure. Explain why chlorine has a low boiling temperature. (2)
January 2020, AS Unit 2, Q5 (1 mark): Which compounds are arranged in order of decreasing boiling temperature? A CH3CH2CH2CH3 > CH3CH2CH2CH2CH3 > CH3CH2CH2CH2CH2CH3 B CH3CH2CH2CH2CH2CH3 > (CH3)2CHCH
January 2020, AS Unit 2, Q11(b) (1 mark): How do the boiling temperatures of ethanol and chloroethane compare, and what is the reason for the difference? (1) Comparison of boiling Reason for the differe
January 2020, AS Unit 2, Q16(a) (6 marks): The boiling temperatures of some isoelectronic hydrides are shown. Hydride CH4 NH3 H2O HF Boiling temperature / K 112 240 373 293 Explain the differences in the
June 2019, AS Unit 2, Q14 (1 mark): Which of these isomers has the highest boiling temperature? Cl A B Cl C Cl Cl D Use this space for any rough working. Anything you write in this space will gain
June 2019, AS Unit 2, Q16(a) (1 mark): Which property is not due to hydrogen bonding? (1) A ice has a lower density than water at 0°C B hydrogen fluoride has a higher boiling temperature than hydroge
June 2019, AS Unit 2, Q16(b) (1 mark): Which diagram best represents a hydrogen bond between two water molecules? (1) 180° O H H H A O H 180° O H H H B O H H 104.5° C O O H H H 104.5° H O H D H O H
June 2019, AS Unit 2, Q19(b)(ii) (2 marks): Explain why iodine is very soluble in cyclohexane but only slightly soluble in water. (2)

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