Balance the redox reaction in basic medium: Cr 3+ + H 2 O 2 → CrO 4 2- + H 2 O. What is the oxidising agent?

H 2 O 2 (H 2 O 2 oxidises Cr 3+ to CrO 4 2- )

Cr 3+ , the species that is itself oxidised to chromate in this reaction

H 2 O, the product formed and therefore not the oxidising agent

OH-, the basic medium ion that does not change oxidation state

Balance the redox reaction in basic medium: Cr 3+ + H 2 O 2 →…

Answer: H₂O₂ (H₂O₂ oxidises Cr³⁺ to CrO₄^2-).

A Cr³⁺, the species that is itself oxidised to chromate in this reaction
B H₂O₂ (H₂O₂ oxidises Cr³⁺ to CrO₄^2-)
C H₂O, the product formed and therefore not the oxidising agent
D OH-, the basic medium ion that does not change oxidation state

Correct answer: B. H₂O₂ (H₂O₂ oxidises Cr³⁺ to CrO₄^2-)

Explanation: Cr goes from +3 to +6 (loses 3e⁻ per Cr; oxidised); H₂O₂ accepts electrons (O goes from -1 to -2): H₂O₂ is the oxidising agent. In basic medium the reaction is: 2Cr³⁺ + 3H₂O₂ + 10OH⁻ → 2CrO₄²⁻ + 8H₂O.

Electron transfer in a redox reaction: zinc loses electrons (oxidised, acts as reducing agent) and copper(II) ions gain those same electrons (reduced, acts as oxidising agent).

Concept context

Master electron transfer in chemistry: assign oxidation states, balance half-reactions, identify oxidising and reducing agents, and connect redox to everyday reactions.

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Balance the redox reaction in basic medium: Cr3+ + H2O2 → CrO42- + H2O. What is the oxidising agent?

Concept context

More Redox Reactions questions

Balance the redox reaction in basic medium: Cr³⁺ + H₂O₂ → CrO₄^2- + H₂O. What is the oxidising agent?