0.1 M solution of `KMnO_(4)` (in acidic medium) may oxidies

Options

A. `0.25 M CO_(2)O_(4)^(-2)`
B. `0.8 M Fe^(+2)`
C. `0.1 M FeC_(2)O_(4)`
D. `0.6 M Cr_(2)O_(7)^(-2)`

Explanation

To solve the question regarding the oxidation of a 0.1 M solution of KMnO4 (potassium permanganate) in acidic medium, we will follow these steps:

### Step 1: Determine the oxidation state of manganese in KMnO4
In KMnO4, the oxidation state of manganese (Mn) is +7.

### Step 2: Identify the reduced form of manganese
When KMnO4 is reduced in acidic medium, manganese is reduced to Mn²⁺, which has an oxidation state of +2.

### Step 3: Calculate the change in oxidation state
The change in oxidation state for manganese from +7 to +2 is:
\[ \text{Change} = +7 - (+2) = 5 \]

### Step 4: Calculate the number of gram equivalents of KMnO4
The number of gram equivalents can be calculated using the formula:
\[ \text{Number of gram equivalents} = \text{Molarity} \times \text{Oxidation number difference} \times \text{Volume (in liters)} \]

Given:
- Molarity of KMnO4 = 0.1 M
- Oxidation number difference = 5
- Volume = 1 L (for calculation purposes)

So,
\[ \text{Number of gram equivalents} = 0.1 \, \text{M} \times 5 \times 1 = 0.5 \, \text{gram equivalents} \]

### Step 5: Analyze the options provided
Now we will analyze the options given in the question to find which one matches the calculated gram equivalents (0.5).

1. **Option A: 0.25 M C2O4²⁻ (Oxalate)**
- Oxidation state of carbon in C2O4²⁻ is +3, and it gets oxidized to CO2 where the oxidation state is +4.
- Change = +4 - (+3) = 1
- Number of gram equivalents = 0.25 M × 1 × 2 (coefficient) = 0.5
- This matches.

2. **Option B: 0.8 M Fe²⁺**
- Oxidation state changes from +2 to +3.
- Change = +3 - (+2) = 1
- Number of gram equivalents = 0.8 M × 1 × 1 = 0.8
- This does not match.

3. **Option C: 0.1 M FeC2O4**
- Oxidation state of iron changes from +2 to +3.
- Change = +3 - (+2) = 1
- Number of gram equivalents = 0.1 M × 1 × 1 = 0.1
- This does not match.

4. **Option D: 0.6 M Cr2O7²⁻ (Dichromate)**
- Oxidation state of chromium changes from +6 to +3.
- Change = +6 - (+3) = 3
- Number of gram equivalents = 0.6 M × 3 × 2 (coefficient) = 3.6
- This does not match.

### Conclusion
Only **Option A** (0.25 M C2O4²⁻) matches the calculated gram equivalents of 0.5 for KMnO4.

### Final Answer
The correct answer is **Option A: 0.25 M C2O4²⁻**.

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