Select the correct statement(s)

Options

A. `CH_(3) SiCl_(3)` undergoes hydrolysis followed by inter molecular elimination of water to form a complex cross linked polymer (i.e silicone)
B. Silicone fluids are thermally stable.
C. In sheet silicone, three oxygen atoms of each tetrahedral are shared with adjacent `SiO_(4)^(4-)` tetrahedrals.
D. Silica is attacked by `HF` and `NaOH`.

Answer

To solve the question regarding the correct statements about silicon and its compounds, we will analyze each statement step by step.

### Step 1: Analyze Statement A
**Statement A:** CH3SiCl3 undergoes hydrolysis followed by intermolecular elimination of water to form a complex cross-linked polymer that is silicon.

**Solution:** This statement is true. CH3SiCl3 (methyltrichlorosilane) can undergo hydrolysis when it reacts with water. The hydrolysis leads to the formation of silanol groups, which can further condense to eliminate water and form siloxane bonds, resulting in a cross-linked polymer structure. This polymerization ultimately leads to the formation of silicon.

### Step 2: Analyze Statement B
**Statement B:** Silicon fluids are thermally stable.

**Solution:** This statement is also true. Silicon-based fluids, such as silicone oils, are known for their thermal stability. They can withstand high temperatures without decomposing, making them suitable for various applications, including lubricants and heat transfer fluids.

### Step 3: Analyze Statement C
**Statement C:** In silicon, three oxygen atoms of each tetrahedral are shared with the adjacent SiO4^4- tetrahedrals.

**Solution:** This statement is correct. In the structure of silicates and silica, each SiO4 tetrahedron shares three of its oxygen atoms with adjacent tetrahedra, forming a network structure. This sharing contributes to the stability and strength of the silicon dioxide network.

### Step 4: Analyze Statement D
**Statement D:** Silica is attacked by HF and NaOH.

**Solution:** This statement is true. Silica (SiO2) reacts with hydrofluoric acid (HF) to form silicon tetrafluoride (SiF4) and water. It also reacts with sodium hydroxide (NaOH) to form sodium silicate (Na2SiO3) and water. Both reactions demonstrate that silica can be attacked by these reagents.

### Conclusion
All four statements (A, B, C, and D) are correct.

### Final Answer:
The correct options for this question are A, B, C, and D.

---