Gold Au goes from an oxidation number of plus 3 to 0 in the reaction. 2 Au raised to the 3 plus power plus 6 cap i raised to the negative right arrow 2 Au plus 3 cap i sub 2 power What describes the Au raised to the 3 plus power ion?

Gold changes from an oxidation number of +3 in Au³⁺ to 0 in Au, so it gains electrons and is reduced. The substance that is reduced causes another substance to be oxidized, so Au³⁺ is the oxidizing agent. Iodide is oxidized to I₂.

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