主題3：氧化還原（一）：練習題

In which of the following species does chlorine have an oxidation number of \(+3\)?

Consider the following disproportionation reaction in alkaline conditions:
\(3Cl_{2} + 6OH^{-} \rightarrow 5Cl^{-} + ClO_{3}^{-} + 3H_{2}O\)
What are the changes in the oxidation number of chlorine in this reaction?

State the oxidation number of sulfur in the following species:
(i) \(S_{8}\)
(ii) \(SO_{4}^{2-}\)

Construct a balanced full ionic equation for the redox reaction between acidified potassium manganate(VII) solution and iron(II) sulfate solution, using the relevant half-equations.

The reaction between chlorine and cold, dilute aqueous sodium hydroxide is a disproportionation reaction. Write a balanced ionic equation for this reaction and explain why it is classified as disproportionation in terms of oxidation numbers.

Consider the reaction between bromate(V) ions and bromide ions in acidic solution:
\( BrO_{3}^{-}(aq) + 5Br^{-}(aq) + 6H^{+}(aq) \rightarrow 3Br_{2}(aq) + 3H_{2}O(l) \)

(a) State the oxidation number of bromine in \( BrO_{3}^{-} \) and in \( Br_{2} \).
(b) Write the two half-equations for this redox reaction, clearly identifying which is oxidation and which is reduction.
(c) Define the term disproportionation and explain, using oxidation numbers, why the reverse of the reaction above is a disproportionation reaction.