`R- OH overset(HX)underset(ZnCI_(3))(to)`

Options

A. R-X
B. Alkene
C. Both (1) & (2)
D. No product

Explanation

To solve the question regarding the reaction of an alcohol (R-OH) with HX in the presence of ZnCl2, we can break down the process into clear steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in this reaction are an alcohol (R-OH) and a hydrogen halide (HX), where X represents a halogen (such as Cl, Br, or I).

**Hint**: Remember that HX can be any hydrogen halide, and the nature of X will influence the reactivity.

2. **Role of ZnCl2**:
Zinc chloride (ZnCl2) acts as a Lewis acid in this reaction. It has a vacant d-orbital that allows it to accept a lone pair of electrons from the oxygen atom of the alcohol.

**Hint**: Lewis acids are electron pair acceptors. Identify the Lewis acid and the Lewis base in the reaction.

3. **Formation of a Coordinate Bond**:
The oxygen atom of the alcohol donates its lone pair to ZnCl2, forming a coordinate covalent bond. This interaction results in the oxygen acquiring a partial positive charge.

**Hint**: Visualize the electron movement; the lone pair from oxygen is shared with ZnCl2.

4. **Formation of Carbocation**:
The bond between the oxygen and the hydrogen of the alcohol weakens, leading to the formation of a carbocation (R+) and a hydroxyl group (OH) that is now associated with ZnCl2.

**Hint**: A carbocation is a positively charged species. Identify where the positive charge is located.

5. **Proton Transfer**:
The HX (where X is a halogen) dissociates into H+ and X-. The H+ ion can then react with the hydroxyl group (OH) to form water (H2O) and leave behind the halide ion (X-).

**Hint**: Consider the stability of the carbocation and the role of the halide ion.

6. **Nucleophilic Attack**:
The halide ion (X-) acts as a nucleophile and attacks the electron-deficient carbocation (R+), resulting in the formation of the alkyl halide (R-X).

**Hint**: Nucleophiles are species that donate electron pairs. Identify the nucleophile in this step.

7. **Final Product**:
The final product of this reaction is an alkyl halide (R-X), where R is the original alkyl group from the alcohol.

**Hint**: Ensure you understand the structure of the final product and how it relates to the starting material.

### Conclusion:
The reaction of an alcohol with HX in the presence of ZnCl2 yields an alkyl halide (R-X) through the formation of a carbocation intermediate and subsequent nucleophilic attack by the halide ion.

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