AQA A-Level Chemistry Paper 3, 2023: Question 22

1 mark · Medium difficulty · Multiple Choice

Identifying the Strongest Reducing Agent This question tests the ability to identify the species that acts as the strongest reducing agent, based on the tendency to lose electrons and reduce other substances, with a focus on halogens and halide ions.

Practise this question

Question

AQA A-Level Chemistry Paper 3, 2023: Question 22
Question text

22 Which species is the strongest reducing agent?

[1 mark]

A F2

B I2

C F–

D I–

Mark scheme

Show the mark scheme Mark scheme for AQA A-Level Chemistry Paper 3, 2023: Question 22

22 D 1 (AO1) I–

How to answer it

Identifying the Strongest Reducing Agent

Question

Which species is the strongest reducing agent?

  • A: F2
  • B: I2
  • C: F−
  • D: I−

Correct Answer: D

The strongest reducing agent is I− because it most readily loses electrons to form I2, thereby reducing another species in the process.

Explanation

A reducing agent donates electrons and is oxidised in the process. The strength of a reducing agent is determined by how easily it loses electrons:

  • I−: Readily loses electrons to form I2, making it the strongest reducing agent among the options.
  • F−: Does not easily lose electrons because fluorine is highly electronegative, making F− a poor reducing agent.
  • F2: A strong oxidising agent, not a reducing agent.
  • I2: A weaker reducing agent than I−, as it is already in its oxidised form.

Teacher Tip

Remember: The strongest reducing agents are typically found at the bottom of Group 7 in their anionic form (e.g., I−). This trend is due to the larger atomic radius and lower electronegativity, making it easier for electrons to be lost.

Final Answer

The correct choice is:

D: I−

Topics

Inorganic Chemistry · 3.2.3 Group 7(17), the Halogens

Question and mark scheme from the AQA A-Level Chemistry examination, Paper 3, 2023. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.