Calculate E0 for the process M→M3++3e Given M→M2++2e,E0=0.44V and M2+→M3++e,E0=-0.77V
Answer
🔋 Standard Electrode Potential Calculation
🧪 Problem Statement
Calculate the standard electrode potential (E°) for the following process:
M → M3+ + 3e−
🔹 Given Data
- Step 1:
M → M²⁺ + 2e⁻, E° = +0.44 V - Step 2:
M²⁺ → M³⁺ + e⁻, E° = −0.77 V
🔍 Step-by-Step Solution
1. Understanding Electrode Potentials
Standard electrode potentials indicate the tendency of species to gain or lose electrons. For consecutive redox steps, the potentials are additive (as long as the direction of electron flow is consistent).
2. Half-Reactions
Step 1: M → M²⁺ + 2e⁻ (E° = +0.44 V)
Step 2: M²⁺ → M³⁺ + e⁻ (E° = −0.77 V)
3. Combine the Reactions
M → M³⁺ + 3e⁻
4. Add Standard Potentials
The overall standard potential is calculated by summing the individual potentials:
E°overall = (+0.44 V) + (−0.77 V) = −0.33 V
✅ Final Answer
E° = −0.33 V
📘 Conclusion
This method shows that when calculating the standard electrode potential for a multi-step redox process, you can simply add the E° values of each step, provided they are sequential and follow the correct electron flow.