Question

Separate this redox reaction into its component half-reactions. 3o2 4cr

Answer 1

Balanced chemical reaction: 3O₂+ 4Cr → 2Cr₂O₃.
a) Oxidation half-reaction: Cr → Cr⁺³ + 3e⁻ /×4; 4Cr → 4Cr⁺³ + 12e⁻.
b) Reduction half-reaction: 4e⁻ + O₂ → 2O⁻² /×3; 12e⁻ + 3O₂ → 6O⁻².
Oxidation is increase of oxidation number (chromium from zero to +3) and reduction is decrease of oxidation number (oxygen from zero to -2).

Answer 2

Answer: The half reactions are written below.

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction reaction occur simultaneously.

Reduction reaction is defined as the reaction in which an atom gains electrons. The oxidation number of the atom gets reduced during this reaction.

$X^{n+}+ne^-\rightarrow X$

Oxidation reaction is defined as the reaction in which an atom looses its electrons. The oxidation number of the atom gets increased during this reaction.

$X\rightarrow X^{n+}+ne^-$

For the given chemical reaction:

$3O_2+4Cr\rightarrow 2Cr_2O_3$

Oxidation half reaction:  $Cr\rightarrow Cr^{3+}+3e^-$     (×  4)

Reduction half reaction:  $O_2+4e^-\rightarrow 2O^{2-}$     (×  3)

Overall reaction:  $4Cr+3O_2\rightarrow 2Cr_2O_3$

Hence, the half reactions are given above.