Ziegler-Natta catalyst is:

Options

A. `TiCl_(4)`
B. `R_(3)Al//TiCl_(4)^(-)`
C. `R_(3)Al`
D. `R_(3)B//TiCl_(2)`

Answer

**Step-by-Step Solution:**

1. **Understanding Ziegler-Natta Catalyst:**
The Ziegler-Natta catalyst is a type of catalyst used in the polymerization of alkenes, particularly for the production of high-density polyethylene (HDPE). It allows for the control of polymer structure and molecular weight.

2. **Identifying Components of the Catalyst:**
The Ziegler-Natta catalyst typically consists of a combination of a transition metal compound and an organoaluminum compound. The most common transition metal used is titanium.

3. **Analyzing the Given Options:**
The options provided are:
- A) Titanium tetrachloride
- B) R3Al and TiCl4
- C) R3Al
- D) R3B and TiCl2

4. **Recognizing the Correct Combination:**
The correct combination for the Ziegler-Natta catalyst includes an organoaluminum compound (R3Al) and titanium tetrachloride (TiCl4). This combination is effective for polymerization.

5. **Selecting the Correct Answer:**
Based on the analysis, the correct answer is option B, which states "R3Al and TiCl4".

6. **Understanding the Reaction:**
The Ziegler-Natta catalyst is used in the polymerization of ethylene (C2H4) to produce high-density polyethylene (HDPE). The reaction occurs under specific conditions, typically at temperatures between 333 K to 343 K and pressures around 6 to 7 atm.

7. **Writing the Reaction:**
The polymerization reaction can be summarized as:
\[ n \text{C}_2\text{H}_4 \xrightarrow{\text{Ziegler-Natta catalyst, 333-343 K, 6-7 atm} } \text{(C}_2\text{H}_4\text{)}_n \text{ (HDPE)} \]

**Final Answer:**
The Ziegler-Natta catalyst is best represented by option B: R3Al and TiCl4.

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