Correct among the following

Options

A. Cs is best oxidising agent due to lowest I.E.
B. `Li^(+)` is best reducing agent due to highest `|Delta_(hyd)H^(Theta)|`
C. `Li^(+)` is best reducing agent due to highest `Delta_(hyd)H^(Theta)`
D. `Cs^(+)` is best oxidising agent due to low `|Delta_(hyd)H^(Theta)|`

Answer

To solve the question regarding the correct statements about the s-block elements, we will analyze each option step by step.

### Step 1: Analyze the first statement
**Statement:** Cesium is the best oxidizing agent due to lowest ionization energy.

- **Explanation:**
- Cesium (Cs) is indeed the largest alkali metal and has the lowest ionization energy among the alkali metals. However, a good oxidizing agent is typically a species that can gain electrons easily.
- Since cesium has a large atomic size and low ionization energy, it tends to lose electrons rather than gain them. Therefore, it acts as a reducing agent, not an oxidizing agent.

**Conclusion:** This statement is incorrect.

### Step 2: Analyze the second statement
**Statement:** Lithium ion (Li⁺) is the best oxidizing agent due to hydration.

- **Explanation:**
- Lithium ion (Li⁺) is small in size, which leads to a high charge density. When Li⁺ is formed, it has a strong tendency to attract water molecules, resulting in significant hydration energy being released.
- The hydration energy contributes to the stability of the Li⁺ ion in solution. Moreover, due to its small size and high charge density, Li⁺ can effectively stabilize the oxidation state, making it a good oxidizing agent as it can facilitate the reduction of other species.

**Conclusion:** This statement is correct.

### Final Conclusion:
- The first statement about cesium being the best oxidizing agent is incorrect.
- The second statement about lithium ion being the best oxidizing agent due to hydration is correct.

### Summary of Correctness:
- **Option 1:** Incorrect
- **Option 2:** Correct