Choose the incorrect statement (s )-

Options

A. 1 mole of `MnO_(4)^(-)` ion can oxidize 10 moles of `Fe^(2+)` ion in acidic medium
B. 1 mole of `Cr_(2)O_(7)^(2-)` ion can oxidize 12 moles of `Fe^ (2+)` ion in acidic medium
C. 2 mole of `Cu_(2)S` can be oxidized by 2.6 moles of `MnO_(4)^(-)` ion in acidic medium `(Cu_(2)StoCu^(2+)SO_(2))`
D. 7.5 mole of `Cu_(2)S` can be oxidized by 10 moles of `Cr_(2)O_(7)^(2-)` ion in acidic medium `(Cu_(2)StoCu^(2+)SO_(2))`

Answer

To solve the problem of identifying the incorrect statements regarding the oxidation-reduction reactions in acetic medium, we will analyze each statement step by step.

### Step 1: Analyze the first statement
The first statement claims that one mole of KF4 can oxidize 10 moles of Fe²⁺ in acetic medium.

1. **Identify the oxidation states**:
- In acetic medium, KF4 (which contains Mn) is reduced from Mn⁷⁺ to Mn²⁺.
- Fe²⁺ is oxidized to Fe³⁺.

2. **Calculate the change in oxidation states**:
- For Mn: Change from +7 to +2 = 5.
- For Fe: Change from +2 to +3 = 1.

3. **Determine the n-factor**:
- n-factor for Mn = 5 (since it changes from +7 to +2).
- n-factor for Fe = 1 (since it changes from +2 to +3).

4. **Calculate equivalents**:
- For Mn: 1 mole × n-factor of 5 = 5 equivalents.
- For Fe: 10 moles × n-factor of 1 = 10 equivalents.

5. **Comparison**:
- The equivalents of oxidizing agent (Mn) = 5.
- The equivalents of reducing agent (Fe) = 10.
- Since 5 ≠ 10, the statement is incorrect.

### Step 2: Analyze the second statement
The second statement claims that K2Cr2O7 can oxidize Fe²⁺.

1. **Identify the oxidation states**:
- In acetic medium, Cr in K2Cr2O7 is reduced from +6 to +3.
- Fe²⁺ is oxidized to Fe³⁺.

2. **Calculate the change in oxidation states**:
- For Cr: Change from +6 to +3 = 3.
- For Fe: Change from +2 to +3 = 1.

3. **Determine the n-factor**:
- n-factor for Cr = 3 (since it changes from +6 to +3).
- n-factor for Fe = 1.

4. **Calculate equivalents**:
- For Cr: 1 mole × n-factor of 3 = 3 equivalents.
- For Fe: 12 moles × n-factor of 1 = 12 equivalents.

5. **Comparison**:
- The equivalents of oxidizing agent (Cr) = 3.
- The equivalents of reducing agent (Fe) = 12.
- Since 3 ≠ 12, the statement is incorrect.

### Step 3: Analyze the third statement
The third statement claims that 2 moles of Cu²⁺ can be oxidized by 2.6 moles of KMnO4 in acetic medium.

1. **Identify the oxidation states**:
- KMnO4 reduces from Mn⁷⁺ to Mn²⁺.
- Cu is oxidized from Cu⁰ to Cu²⁺.

2. **Calculate the change in oxidation states**:
- For Mn: Change from +7 to +2 = 5.
- For Cu: Change from +0 to +2 = 2.

3. **Determine the n-factor**:
- n-factor for Mn = 5.
- n-factor for Cu = 2.

4. **Calculate equivalents**:
- For Mn: 2.6 moles × n-factor of 5 = 13 equivalents.
- For Cu: 2 moles × n-factor of 2 = 4 equivalents.

5. **Comparison**:
- The equivalents of oxidizing agent (Mn) = 13.
- The equivalents of reducing agent (Cu) = 4.
- Since 13 ≠ 4, the statement is incorrect.

### Step 4: Analyze the fourth statement
The fourth statement claims that 7.5 moles of a certain compound can be oxidized by 10 moles of another compound.

1. **Identify the n-factor**:
- Assume the n-factor of the first compound is 8.
- Assume the n-factor of the second compound is 6.

2. **Calculate equivalents**:
- For the first compound: 7.5 moles × n-factor of 8 = 60 equivalents.
- For the second compound: 10 moles × n-factor of 6 = 60 equivalents.

3. **Comparison**:
- The equivalents of both sides are equal (60 = 60), hence this statement is correct.

### Conclusion
The incorrect statements are the first three statements regarding the oxidation-reduction reactions in acetic medium.