The `E_(M^(3+)//M^(2+)^@` values for ` Cr`, Mn, Fe and ` Co` are ` 0.41, + 1.57 , + 0.77` and `+1, 97 V` respectively. For which one of these metals the change ub oxidation state from ` =2 ` to ` 3` is easiest :

Options

A. `Fe`
B. `Mn`
C. `Cr`
D. `Co`

Explanation

To determine which metal has the easiest change in oxidation state from +2 to +3, we need to analyze the given standard reduction potentials (E°) for the metals:

1. **Given Reduction Potentials:**
- Chromium (Cr): \( E° = 0.41 \, V \)
- Manganese (Mn): \( E° = 1.57 \, V \)
- Iron (Fe): \( E° = 0.77 \, V \)
- Cobalt (Co): \( E° = 1.97 \, V \)

2. **Understanding Reduction and Oxidation:**
- The reduction potential indicates how easily a species can gain electrons (be reduced).
- Conversely, a lower reduction potential means that the species is more likely to lose electrons (be oxidized).
- Therefore, to find which metal is easiest to oxidize from +2 to +3, we need to look for the metal with the lowest reduction potential.

3. **Comparing the Reduction Potentials:**
- Among the given values, the lowest reduction potential is for Chromium (0.41 V).
- The higher the reduction potential, the less likely the species is to be oxidized. Thus, Chromium, with the lowest reduction potential, has the highest tendency to be oxidized.

4. **Conclusion:**
- Since Chromium has the lowest reduction potential, it is the metal for which the change in oxidation state from +2 to +3 is easiest.

**Final Answer:**
The metal for which the change in oxidation state from +2 to +3 is easiest is **Chromium (Cr)**.

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