Edexcel A-Level Chemistry AS Paper 2, June 2017: Question 1

1 mark · Easy difficulty · Multiple Choice

Identify which of the given compounds does not have hydrogen bonding between its molecules.

Practise this question

Question

Multiple choice question asking which compound does not have hydrogen bonding between its molecules. A table lists four options: A, fluoromethane (CH3F); B, hydrogen fluoride (HF); C, hydrogen peroxide (H2O2); D, methanol (CH3OH).
Question text

1 Which compound does not have hydrogen bonding between its molecules?

Name of compound Formula of compound

A fluoromethane CH3F

B hydrogen fluoride HF

C hydrogen peroxide H2O2

D methanol CH3OH

(Total for Question 1 = 1 mark)

Mark scheme

Show the mark scheme Mark scheme showing that option A is the correct answer (1 mark), with explanations for why options B, C, and D are incorrect.

Question

Answer Mark

Number

1 1. The only correct answer is A (1)

B is not correct because fluorine is very electronegative and has a suitable lone pair of

electrons for hydrogen bonding.

C is not correct because has hydrogen bonding; compare with water.

D is not correct because alcohols can hydrogen bond; compare with water.

(Total for Question 1 = 1 mark)

How to answer it

Identifying Hydrogen Bonding in Molecules

What this question tests

This question assesses your understanding of intermolecular forces, specifically the strict structural requirements needed for hydrogen bonding to occur between molecules. You must recall that hydrogen bonding requires a hydrogen atom covalently bonded directly to a highly electronegative atom (N, O, or F) which also possesses a lone pair of electrons.

Question 1 (Multiple Choice)

Which compound does not have hydrogen bonding between its molecules?

✅ Correct Answer: A (fluoromethane, CH₃F )

Fluoromethane has a carbon-fluorine bond. Although fluorine is extremely electronegative, the hydrogen atoms in CH₃F are covalently bonded to carbon, not fluorine. Therefore, it cannot form intermolecular hydrogen bonds.

💡 Key Knowledge: The Hydrogen Bond Rule

  • Must feature an H atom covalently bonded to N , O , or F .
  • The N , O , or F atom must possess at least one lone pair of electrons.
  • All other options ( HF , H₂O₂ , CH₃OH ) feature H directly attached to O or F .

🧠 Exam Technique

Always draw out or mentally visualise the bonding connectivity (structural formula) when evaluating intermolecular forces. Do not let the presence of a single electronegative atom like fluorine trick you into assuming hydrogen bonding is automatically present!

❌ Common Errors

Students frequently lose marks in intermolecular force questions by assuming any molecule containing fluorine, oxygen, or nitrogen automatically forms hydrogen bonds, failing to check whether the hydrogen atom is bonded directly to that electronegative atom.

Mark Scheme Breakdown: 1 mark awarded for selecting A. No other options are accepted.

Topics

Physical Chemistry · Topic 2: Bonding and Structure

Question and mark scheme from the Edexcel A-Level Chemistry examination, AS Paper 2, June 2017. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.