Assertion : The bond energy and bond formation energy of a particular bond are equal in magnitude but opposite in sign.
Reason : The process of bond formation requires absorption of energy but the process of breaking of bond involves liberation of energy.

Options

A. If both Assertion and Reason are CORRECT and Reason is the CORRECT explanation of the Assertion.
B. If both Assertion and Reason are CORRECT but Reason is not the CORRECT explanation of the Assertion.
C. If Assertion is CORRECT but Reason is INCORRECT.
D. If Assertion is INCORRECT but Reason is CORRECT.

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding Bond Energy**:
- Bond energy is defined as the amount of energy required to break one mole of a bond in a molecule. This process requires energy input, which means it is endothermic. Therefore, the bond energy is a positive value.

2. **Understanding Bond Formation Energy**:
- Conversely, bond formation energy refers to the energy released when a bond is formed between atoms. This process is exothermic, meaning it releases energy. Thus, the bond formation energy is a negative value.

3. **Relationship Between Bond Energy and Bond Formation Energy**:
- The assertion states that the bond energy and bond formation energy are equal in magnitude but opposite in sign. This is true because:
- When you break a bond (bond energy), you need to put in energy (positive value).
- When you form a bond (bond formation energy), energy is released (negative value).
- Therefore, we can express this relationship mathematically as:
\[ \text{Bond Energy} = -\text{Bond Formation Energy} \]

4. **Evaluating the Reason**:
- The reason provided states that the process of bond formation requires absorption of energy, which is incorrect. In reality, bond formation releases energy.
- The second part of the reason states that breaking a bond involves liberation of energy, which is also incorrect. Breaking a bond requires energy input.

5. **Conclusion**:
- The assertion is correct: bond energy and bond formation energy are equal in magnitude but opposite in sign.
- The reason is incorrect: bond formation involves the release of energy, not absorption.

### Final Answer:
- The assertion is correct, but the reason is incorrect.