Question

consider the following reaction and identify the substance that is the oxidizing agent.
3 mg(s) + 2 cr(c₂h₃o₂)₃(aq) → 2 cr(s) + 3 mg(c₂h₃o₂)₂(aq)
mg in mg(c₂h₃o₂)₂(aq)
cr in cr(c₂h₃o₂)₃(aq)
cr(s)
mg(s)

Explanation:

Step1: Determine oxidation states

• In \(Mg(s)\), oxidation state of \(Mg\) is \(0\). In \(Mg(C_2H_3O_2)_2(aq)\), oxidation state of \(Mg\) is \(+2\) (since acetate ion \((C_2H_3O_2^-)\) has charge \(-1\) and compound is neutral). So \(Mg\) is oxidized (loses electrons).
• In \(Cr(C_2H_3O_2)_3(aq)\), let oxidation state of \(Cr\) be \(x\). Since acetate ion \((C_2H_3O_2^-)\) has charge \(-1\) and compound is neutral: \(x+3\times(-1) = 0\), so \(x = +3\). In \(Cr(s)\), oxidation state of \(Cr\) is \(0\). So \(Cr\) is reduced (gains electrons).

Step2: Identify oxidizing agent

Oxidizing agent is the substance that gets reduced. \(Cr\) in \(Cr(C_2H_3O_2)_3(aq)\) is reduced from \(+3\) to \(0\).

Answer:

Cr in \(Cr(C_2H_3O_2)_3(aq)\)