Give the decreasing order of `E_((M^(3+))/(M^(2+))^(c-)` Value for the following:
(a). `Co(Z=27)`
(b). `Mn(Z=25)`
(c). `Fe(Z=26)`
(d). `Cr(Z=24)`

Explanation

To determine the decreasing order of the reduction potential \( E_{(M^{3+}/M^{2+})} \) for cobalt, manganese, iron, and chromium, we will analyze the electronic configurations and the stability of the oxidation states.

### Step 1: Identify the electronic configurations
1. **Cobalt (Co, Z=27)**:
- Electronic configuration: \( [Ar] 3d^7 4s^2 \)
2. **Manganese (Mn, Z=25)**:
- Electronic configuration: \( [Ar] 3d^5 4s^2 \)
3. **Iron (Fe, Z=26)**:
...