Given :
`Co^(3+)+e^(-)rarr Co^(2+), E^(@)=+1.181V`
`Pb^(4+)+2e^(-)rarrPb^(2+),E^(@)=+1.67V`
`Ce^(4+)+e^(-) rarr Ce^(3+), E^(@)=+1.61V`
`Bi^(3+)+3e^(-)rarr Bi, E^(@)=+0.20V`
Oxidizing power of the species will increase in the order:

Options

A. `Ce^(4+)lt Pb^(4+) lt Bi^(3+) lt Co`
B. `Co^(3+) lt Ce^(4+) lt Bi^(3+) lt Pb^(4+)`
C. `Bi^(3+) ltCe^(4+) lt Pb^(4+) lt Co^(3+)`
D. `Co^(3+) lt Pb^(4+) lt Ce^(4+) lt Bi^(3+)`

Explanation

To determine the increasing order of oxidizing power of the given species based on their standard reduction potentials, we can follow these steps:

### Step 1: List the Given Reactions and Their Standard Reduction Potentials
We have the following reactions and their corresponding standard reduction potentials (E°):

1. \( \text{Co}^{3+} + e^- \rightarrow \text{Co}^{2+}, \quad E^\circ = +1.181 \, \text{V} \)
2. \( \text{Pb}^{4+} + 2e^- \rightarrow \text{Pb}^{2+}, \quad E^\circ = +1.67 \, \text{V} \)
3. \( \text{Ce}^{4+} + e^- \rightarrow \text{Ce}^{3+}, \quad E^\circ = +1.61 \, \text{V} \)
4. \( \text{Bi}^{3+} + 3e^- \rightarrow \text{Bi}, \quad E^\circ = +0.20 \, \text{V} \)

### Step 2: Identify the Oxidizing Power
The oxidizing power of a species is directly related to its standard reduction potential. A higher reduction potential indicates a stronger oxidizing agent.

### Step 3: Compare the Reduction Potentials
Now, we will compare the given standard reduction potentials:

- \( \text{Pb}^{4+} \) has the highest reduction potential of \( +1.67 \, \text{V} \)
- \( \text{Ce}^{4+} \) follows with \( +1.61 \, \text{V} \)
- \( \text{Co}^{3+} \) comes next with \( +1.181 \, \text{V} \)
- \( \text{Bi}^{3+} \) has the lowest reduction potential of \( +0.20 \, \text{V} \)

### Step 4: Arrange in Increasing Order of Oxidizing Power
Based on the reduction potentials, we can arrange the species in increasing order of their oxidizing power:

1. \( \text{Bi}^{3+} \) (lowest oxidizing power)
2. \( \text{Co}^{3+} \)
3. \( \text{Ce}^{4+} \)
4. \( \text{Pb}^{4+} \) (highest oxidizing power)

### Final Order
Thus, the increasing order of oxidizing power of the species is:
\[ \text{Bi}^{3+} < \text{Co}^{3+} < \text{Ce}^{4+} < \text{Pb}^{4+} \]