The standard `E_(red)^(@)`Values if A, B and C are `+ 0.68V`, -`0.76V`, `-0.50V` respectively.
The order of their reducing power is :

Options

A. AgtBgtC
B. AgtCgtB
C. CgtBgtA
D. BgtCgtA

Explanation

To determine the order of reducing power for the species A, B, and C based on their standard reduction potentials, we can follow these steps:

### Step 1: Identify the Standard Reduction Potentials
We have the following standard reduction potentials:
- \( E^\circ_{red} \) for A = +0.68 V
- \( E^\circ_{red} \) for B = -0.76 V
- \( E^\circ_{red} \) for C = -0.50 V

### Step 2: Understand Reducing Power
The reducing power of a species is related to its tendency to lose electrons. A species with a more negative standard reduction potential is a stronger reducing agent because it is more willing to donate electrons.

### Step 3: Compare the Values
Now we compare the standard reduction potentials:
- A: +0.68 V (least reducing power)
- C: -0.50 V (moderate reducing power)
- B: -0.76 V (strongest reducing power)

### Step 4: Determine the Order of Reducing Power
From the comparison:
- B has the most negative value (-0.76 V), making it the strongest reducing agent.
- C has a less negative value (-0.50 V), making it a weaker reducing agent than B but stronger than A.
- A has the highest value (+0.68 V), making it the weakest reducing agent.

Thus, the order of reducing power is:
**B > C > A**

### Final Answer
The order of reducing power is: **B > C > A**

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