Question 21 of 31advanced🔍 AnalyzeShort Answer2 marks

Why does the following reaction occur? XeO₆⁴⁻ (aq) + 2F⁻ (aq) + 6H⁺(aq) → XeO₃(g) + F₂(g) + 3H₂O(l) What conclusion about the compound Na₄XeO₆ (of which XeO₆⁴⁻ is a part) can be drawn from the reaction.

Correct Answer

(i) The reaction occurs because it is a redox reaction. In this reaction, the oxidation state of Xe decreases from +8+8 in XeO64−\text{XeO}_6^{4-} to +6+6 in XeO3\text{XeO}_3, meaning Xe is reduced. Simultaneously, the oxidation state of F increases from −1-1 in F−\text{F}^- to 00 in F2\text{F}_2, meaning F is oxidised. Since both oxidation and reduction occur simultaneously, the reaction takes place.

(ii) The conclusion drawn is that the compound Na4XeO6\text{Na}_4\text{XeO}_6 (or XeO64−\text{XeO}_6^{4-}) acts as an extremely powerful oxidising agent. This is because it is capable of oxidising F−\text{F}^- ions to F2\text{F}_2 gas, which is otherwise very difficult to achieve by chemical means.

Exercise: EXERCISES | Q: 7.16 | (Page Page 19)
For More Understanding

Explanation

In the given reaction, Xe undergoes reduction and F undergoes oxidation. The oxidation state of Xe changes from +8 to +6, while F changes from -1 to 0. The context highlights that converting F- to F2 is extremely difficult and usually requires electrolytic oxidation. Therefore, a chemical agent that can oxidize F- to F2 must be an exceptionally strong oxidizing agent.

Solution Steps

  1. Step 1: Determine the oxidation states of Xe and F in reactants and products. Xe in XeO64−\text{XeO}_6^{4-} is +8+8 and in XeO3\text{XeO}_3 is +6+6. F in F−\text{F}^- is −1-1 and in F2\text{F}_2 is 00.

  2. Step 2: Identify the redox process. Xe is reduced (+8→+6+8 \rightarrow +6) and F is oxidised (−1→0-1 \rightarrow 0). This simultaneous oxidation and reduction drives the reaction.

  3. Step 3: Draw the conclusion. Since XeO64−\text{XeO}_6^{4-} oxidises F−\text{F}^- to F2\text{F}_2 (which is very hard to do chemically), Na4XeO6\text{Na}_4\text{XeO}_6 is a very powerful oxidising agent.

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