Assertion: Formation of `Cl^(-)` ion is exothermic wheres `O^(2-)` ion formation is endothermic.
Reason: `EA_(2)` of oxygen is endothermic and greater than its exothermic `EA_(1)` value of oxygen.

Options

A. If both assertion and reason are true annd the reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but the reason is false
D. if assertion is false but the reason is true

Answer

To solve the question, we will analyze the assertion and the reason provided:

### Step 1: Understand the Assertion
The assertion states that the formation of the `Cl^(-)` ion is exothermic, while the formation of the `O^(2-)` ion is endothermic.

**Explanation**:
- Chlorine (Cl) has a high electron affinity, meaning it releases energy when it gains an electron to form `Cl^(-)`. This process is exothermic because energy is released.
- Oxygen (O), on the other hand, when it gains two electrons to form `O^(2-)`, goes through two steps. The first step, gaining one electron to form `O^(-)`, is exothermic, but the second step, gaining another electron to form `O^(2-)`, is endothermic due to electron-electron repulsion.

### Step 2: Analyze the Reason
The reason given is that the second electron affinity (EA2) of oxygen is endothermic and greater than its first electron affinity (EA1).

**Explanation**:
- The first electron affinity (EA1) of oxygen is exothermic, meaning energy is released when it gains the first electron. However, when oxygen tries to gain a second electron, the negatively charged `O^(-)` ion experiences repulsion from the incoming electron. This repulsion requires energy to overcome, making the second electron affinity (EA2) endothermic.
- Since EA2 is greater than EA1, it indicates that the energy required to add the second electron is more than the energy released when the first electron is added.

### Conclusion
Both the assertion and the reason are correct. The formation of `Cl^(-)` is indeed exothermic, while the formation of `O^(2-)` is endothermic due to the reasons stated.

### Final Answer
- **Assertion**: True
- **Reason**: True
- **Conclusion**: Both the assertion and reason are correct, and the reason correctly explains the assertion.

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