Which of the following reactions does not involved absorption energy?
I `O(g)+e^(-)toO^(-)(g)`
II `S(g)+e^(-)toS^(-)(g)`
III `O^(-)(g)+e^(-)toO^(2-)(g)`
IV) `Cl(g)+e^(-)toCl^(-)(g)`

Options

A. Only II
B. I and III
C. I , II and III
D. I , I and IV

Explanation

To determine which of the following reactions does not involve the absorption of energy, we need to analyze each reaction based on the concept of electron affinity and whether energy is released or absorbed when an electron is added to an atom or ion.

1. **Reaction I: O(g) + e⁻ → O⁻(g)**
- In this reaction, an electron is added to a neutral oxygen atom to form an oxide ion (O⁻). The process of adding an electron to a neutral atom generally releases energy (exothermic) because the electron is attracted to the positively charged nucleus. Therefore, this reaction does not involve absorption of energy.

2. **Reaction II: S(g) + e⁻ → S⁻(g)**
- Similar to the first reaction, adding an electron to a neutral sulfur atom to form a sulfide ion (S⁻) also releases energy. This is because the added electron is attracted to the nucleus of the sulfur atom. Hence, this reaction also does not involve absorption of energy.

3. **Reaction III: O⁻(g) + e⁻ → O²⁻(g)**
- In this case, we are adding an electron to an already negatively charged oxide ion (O⁻) to form a doubly charged oxide ion (O²⁻). Since we are adding an electron to a negatively charged species, there is electron-electron repulsion. To overcome this repulsion, energy must be supplied, making this reaction endothermic. Thus, this reaction involves absorption of energy.

4. **Reaction IV: Cl(g) + e⁻ → Cl⁻(g)**
- Here, an electron is added to a neutral chlorine atom to form a chloride ion (Cl⁻). This process also releases energy as the electron is attracted to the chlorine nucleus. Therefore, this reaction does not involve absorption of energy.

**Conclusion:**
The reactions that do not involve absorption of energy are:
- Reaction I: O(g) + e⁻ → O⁻(g)
- Reaction II: S(g) + e⁻ → S⁻(g)
- Reaction IV: Cl(g) + e⁻ → Cl⁻(g)

The only reaction that involves absorption of energy is:
- Reaction III: O⁻(g) + e⁻ → O²⁻(g)

Thus, the answer to the question is that Reaction III is the only one that involves absorption of energy.