Select correct statement(s) is /are :

Options

A. In `AsH_(3)` molecule lone pair at central atom is present in almost pure s-orbital
B. Number of `p pi -d pi` bond in `SO_(3) and SO_(2)` are same
C. `NF_(3)` is better Lewis base than `NCl_(3)`
D. Stable oxidation state of Lead is `+2`

Explanation

To solve the question of selecting the correct statement(s) regarding chemical bonding, we will analyze each option provided in the question step by step.

### Step-by-Step Solution:

1. **Analyzing Option A:**
- **Statement:** "In AsH3 molecule, the lone pair at the central atom is present in almost pure s orbital."
- **Explanation:** Arsenic (As) is in group 15 of the periodic table, with the electronic configuration of [Ar] 4s² 4p³. In AsH3, arsenic forms three bonds with hydrogen atoms, using three of its p orbitals. The remaining lone pair of electrons will be in the 4s orbital. Thus, the lone pair is indeed in an almost pure s orbital.
- **Conclusion:** **Option A is correct.**

2. **Analyzing Option B:**
- **Statement:** "The number of p-pi d-pi bonds in SO3 and SO2 are the same."
- **Explanation:** In SO3, sulfur forms two p-pi d-pi bonds with oxygen, while in SO2, sulfur forms only one p-pi d-pi bond. Therefore, the number of p-pi d-pi bonds in SO3 and SO2 is not the same.
- **Conclusion:** **Option B is incorrect.**

3. **Analyzing Option C:**
- **Statement:** "NF3 is a better Lewis base than NCl3."
- **Explanation:** A Lewis base is defined as a species that can donate a pair of electrons. In NF3, fluorine is highly electronegative and holds onto its electrons tightly, making it a poor Lewis base. In contrast, NCl3 has chlorine, which is less electronegative than fluorine, allowing it to donate electrons more easily. Therefore, NCl3 is a better Lewis base than NF3.
- **Conclusion:** **Option C is incorrect.**

4. **Analyzing Option D:**
- **Statement:** "The stable oxidation state of lead is +2."
- **Explanation:** Lead (Pb) belongs to group 14 of the periodic table. As we move down the group, the +2 oxidation state becomes more stable compared to the +4 oxidation state. Thus, the +2 oxidation state is indeed the most stable for lead.
- **Conclusion:** **Option D is correct.**

### Final Answer:
The correct statements are **A and D.**