Q58 · Practice questionComplex familiar4 marks
QUESTION 58 (4 marks)
Vanadium(V) oxide, , is reduced to in acidic solution.
a) Determine the initial vanadium oxidation state. [1 marks]
b) Write the balanced reduction half-equation. [3 marks]
WORKED SOLUTION
4 marksPractice marking scheme
Vanadium is +5; .
Five oxygens contribute −10, so two vanadium atoms contribute +10. Each vanadium gains two electrons. Balance oxygen with five waters and hydrogen with ten H⁺.
- Determines +5. [1 marks]
- Balances two vanadium atoms and five waters. [1 marks]
- Adds ten H⁺. [1 marks]
- Adds four electrons on the reactant side. [1 marks]
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