Final answer:
In the given redox reaction, Zn²⁺ (aq) ions are the oxidizing agent, as they gain electrons and get reduced to solid zinc (Zn). Thus, the correct answer is c, Zn²⁺ (aq).
Step-by-step explanation:
In the reaction 3 Zn²⁺ (aq) + 2 Al (s) → 3 Zn (s) + 2 Al³⁺ (aq), the oxidizing agent is the species that gets reduced by gaining electrons. In this redox reaction, the aluminum (Al in the solid state) is oxidized to Al³⁺ (aq), as it loses three electrons:
Al(s) → Al³⁺ (aq) + 3e⁻
Meanwhile, zinc ions (Zn²⁺ in the aqueous state) are reduced to Zinc (Zn in the solid state) by gaining two electrons per ion:
Zn²⁺ (aq) + 2e⁻ → Zn(s)
Therefore, the Zn²⁺ (aq) ions are the oxidizing agent, as they accept electrons during the reaction. The correct choice is c, Zn²⁺ (aq).