On the basis of your results, arrange the three metals studied in this experiment (zinc, copper, and lead) in order of decreasing ease of oxidation (i.e., list the most easily oxidized metal first). Briefly justify your answer. Results from the experiment: Voltage produced from cell using Zn/Zn2+ and Pb/Pb2+ half-cells = 0.595 V Voltage produced from cell using Zn/Zn2+ and Cu/Cu2+ half-cells = 1.074 V Voltage produced from cell using Cu/Cu2+ and Pb/Pb2+ half-cells = 0.480 V
The Correct Answer and Explanation is:
To determine the order of the metals in terms of their ease of oxidation (most easily oxidized to least easily oxidized), we can use the cell voltages provided from the experiment and the concept of standard electrode potentials.
Experiment Data:
- Zn/Zn²⁺ and Pb/Pb²⁺ half-cells: 0.595 V
- Zn/Zn²⁺ and Cu/Cu²⁺ half-cells: 1.074 V
- Cu/Cu²⁺ and Pb/Pb²⁺ half-cells: 0.480 V
The voltage produced in a galvanic cell depends on the difference in the standard electrode potentials (E°) of the two half-cells. The cell potential is given by:Cell Potential (E°)=E°(cathode)−E°(anode)\text{Cell Potential (E°)} = E°(\text{cathode}) – E°(\text{anode})Cell Potential (E°)=E°(cathode)−E°(anode)
In a galvanic cell, the metal that is more easily oxidized (i.e., the anode) will have a more negative electrode potential, while the metal that is reduced (i.e., the cathode) will have a more positive electrode potential.
Step 1: Calculate Relative Electrode Potentials
From the data provided:
- For Zn/Zn²⁺ and Pb/Pb²⁺, the voltage is 0.595 V. Since zinc is a more active metal, it will be oxidized at the anode, and Pb will be reduced at the cathode.
- For Zn/Zn²⁺ and Cu/Cu²⁺, the voltage is 1.074 V. Zinc is oxidized at the anode, and copper is reduced at the cathode.
- For Cu/Cu²⁺ and Pb/Pb²⁺, the voltage is 0.480 V. Copper is oxidized at the anode, and Pb is reduced at the cathode.
Step 2: Determine Relative Oxidation Tendencies
- Zinc (Zn): Zinc produces the highest voltage when paired with copper (1.074 V) and a moderate voltage with lead (0.595 V). This indicates that zinc is the most easily oxidized metal in this set, as it tends to lose electrons more readily than copper or lead.
- Copper (Cu): Copper has a voltage of 0.480 V when paired with lead, which is the lowest voltage among the three pairs. This indicates copper is less easily oxidized than zinc, but more easily oxidized than lead.
- Lead (Pb): Lead consistently produces the lowest voltage when paired with the other metals (0.595 V with zinc and 0.480 V with copper). This suggests that lead is the least easily oxidized of the three metals.
Conclusion:
The order of decreasing ease of oxidation (from most easily oxidized to least easily oxidized) is:
- Zinc (Zn)
- Copper (Cu)
- Lead (Pb)
This ranking is based on the voltage data, where higher cell voltages correspond to greater ease of oxidation (since the metal in the anode is oxidized). Therefore, zinc is the most easily oxidized, followed by copper, and lead is the least easily oxidized.
