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When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products - CIE - A-Level Chemistry - Question 17 - 2018 - Paper 1
Question 17
When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products. However when concentrated sulfuric ... show full transcript
Worked Solution & Example Answer:When concentrated sulfuric acid is added to solid sodium bromide, bromine gas is produced, along with a number of other products - CIE - A-Level Chemistry - Question 17 - 2018 - Paper 1
Step 1
What is the reason for this difference?
Answer
The correct answer is D. The bromide ion is a stronger reducing agent than the chloride ion.
Explanation
In the reaction involving concentrated sulfuric acid and sodium bromide, bromide ions (Br⁻) act as reducing agents, which means they can undergo oxidation to form bromine gas (Br₂). This is due to the higher oxidizing tendency of sulfuric acid compared to hydrochloric acid.
On the other hand, when concentrated sulfuric acid is reacted with sodium chloride, chloride ions (Cl⁻) do not exhibit a similar reducing capability. Hence, the products formed are only hydrogen chloride (HCl) and sodium hydrogensulfate (NaHSO₄).
This difference in behavior is primarily attributed to the relative strengths of bromide and chloride ions as reducing agents in the presence of a strong oxidizing agent like sulfuric acid.