Zn + CuSO 4 → ZnSO 4 + Cu

Analysis

To identify the reducing agent, we need to analyze the changes in the oxidation states of the elements involved in the reaction. A reducing agent is the substance that gets oxidized (loses electrons) during a chemical reaction.

Concept: Oxidation and Reduction (Redox)

• Oxidation: The process of losing electrons, which results in an increase in oxidation state.
• Reduction: The process of gaining electrons, which results in a decrease in oxidation state.
• Reducing Agent: The substance that causes reduction by donating electrons; therefore, the reducing agent itself is oxidized.

Step-by-Step Solution

1. Assign oxidation states to each element: • Reactants: • Zn (elemental form) = 0 • CuSO$_4$: Cu is +2, SO$_4$ is -2. • Products: • ZnSO$_4$: Zn is +2, SO$_4$ is -2. • Cu (elemental form) = 0

2. Track the changes: • Zinc (Zn): Oxidation state changes from 0 to +2. This is an increase in oxidation state, meaning Zn has lost electrons (Oxidation). • Copper (Cu): Oxidation state changes from +2 to 0. This is a decrease in oxidation state, meaning Cu has gained electrons (Reduction).

3. Identify the roles: • Since Zn lost electrons and was oxidized, it acts as the reducing agent. • Since Cu$^{2+}$ gained electrons and was reduced, CuSO$_4$ acts as the oxidizing agent.

Conclusion

Because Zinc (Zn) is the substance that is oxidized, it is the reducing agent in this reaction.

Exam Tip: Remember the mnemonic OIL RIG: Oxidation Is Loss (of electrons), Reduction Is Gain (of electrons). If you find the substance that loses electrons, you have found the reducing agent!