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In which conversion is the metal reduced? A Cr₂O₇²⁻ → CrO₄²⁻ B MnO₄²⁻ → MnO₄⁻ C TiO₂ → TiO₄²⁻ D VO₃⁻ → VO⁺ - AQA - A-Level Chemistry - Question 11 - 2020 - Paper 3
Question 11
In which conversion is the metal reduced? A Cr₂O₇²⁻ → CrO₄²⁻ B MnO₄²⁻ → MnO₄⁻ C TiO₂ → TiO₄²⁻ D VO₃⁻ → VO⁺
Worked Solution & Example Answer:In which conversion is the metal reduced? A Cr₂O₇²⁻ → CrO₄²⁻ B MnO₄²⁻ → MnO₄⁻ C TiO₂ → TiO₄²⁻ D VO₃⁻ → VO⁺ - AQA - A-Level Chemistry - Question 11 - 2020 - Paper 3
Step 1
D VO₃⁻ → VO⁺
Answer
In the conversion D, VO₃⁻ to VO⁺, the vanadium (V) in vanadate is reduced. The reduction occurs as the oxidation state of vanadium changes from +5 in VO₃⁻ to +4 in VO⁺. This indicates that the metal has gained electrons, therefore confirming that this is the correct conversion where the metal is reduced.