Which of the following is not an example of redox reaction?

Options

A. `CuO+H_(2)toCu+H_(2)O`
B. `Fe_(2)O_(3)+3COto3Fe+3CO_(2)`
C. `2K+F_(2)to2KF`
D. `BaCl_(2)+H_(2)SO_(4)toBaSO_(4)+2HCl`

Explanation

To determine which of the given reactions is not an example of a redox reaction, we need to analyze the oxidation states of the elements involved in each reaction. A redox reaction involves the transfer of electrons, which results in changes in oxidation states for the elements involved.

### Step-by-Step Solution:

1. **Identify the Reactions**: We have four reactions to analyze:
- Reaction 1: CuO + H2 → Cu + H2O
- Reaction 2: Fe2O3 + 3Co → 2Fe + 3Co2
- Reaction 3: 2K + Fe2 → 2KF
- Reaction 4: BaCl2 + H2SO4 → BaSO4 + 2HCl

2. **Analyze Reaction 1**:
- **Oxidation States**:
- CuO: Cu = +2, O = -2
- H2: H = 0
- Cu: Cu = 0
- H2O: H = +1, O = -2
- **Changes**:
- Cu: +2 to 0 (reduction)
- H: 0 to +1 (oxidation)
- **Conclusion**: This is a redox reaction.

3. **Analyze Reaction 2**:
- **Oxidation States**:
- Fe2O3: Fe = +3, O = -2
- Co: Co = 0
- Fe: Fe = 0
- Co2: C = +4, O = -2
- **Changes**:
- Fe: +3 to 0 (reduction)
- Co: 0 to +2 (oxidation)
- **Conclusion**: This is a redox reaction.

4. **Analyze Reaction 3**:
- **Oxidation States**:
- K: K = 0
- Fe2: Fe = 0
- KF: K = +1, F = -1
- **Changes**:
- K: 0 to +1 (oxidation)
- F: 0 to -1 (reduction)
- **Conclusion**: This is a redox reaction.

5. **Analyze Reaction 4**:
- **Oxidation States**:
- BaCl2: Ba = +2, Cl = -1
- H2SO4: H = +1, S = +6, O = -2
- BaSO4: Ba = +2, S = +6, O = -2
- HCl: H = +1, Cl = -1
- **Changes**:
- Ba: +2 to +2 (no change)
- Cl: -1 to -1 (no change)
- H: +1 to +1 (no change)
- S: +6 to +6 (no change)
- **Conclusion**: There are no changes in oxidation states; therefore, this is not a redox reaction.

6. **Final Answer**: The reaction that is not an example of a redox reaction is **BaCl2 + H2SO4 → BaSO4 + 2HCl**.