In the acid catalyzed dehydration of alcohols to alkenes, the intermediate species formed is

Options

A. free radical
B. carbocation
C. carbanion
D. hydronium ion

Answer

To solve the question regarding the intermediate species formed in the acid-catalyzed dehydration of alcohols to alkenes, we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- The reaction involves the dehydration of an alcohol in the presence of an acid catalyst. The general formula for this reaction can be represented as:
\[ \text{Alcohol} \xrightarrow{\text{Acid}} \text{Alkene} + \text{H}_2\text{O} \]

2. **Identifying the Acid Catalyst**:
- A common acid used for this dehydration process is sulfuric acid (H₂SO₄). This acid acts as a dehydrating agent.

3. **Protonation of the Alcohol**:
- The first step in the mechanism is the protonation of the alcohol's hydroxyl group (OH) by the acid. The lone pair of electrons on the oxygen atom of the alcohol attacks a proton (H⁺) from the acid, forming an oxonium ion:
\[ \text{R-OH} + \text{H}^+ \rightarrow \text{R-OH}_2^+ \]
- Here, R represents the alkyl group.

4. **Formation of the Carbocation**:
- The oxonium ion (R-OH₂⁺) is unstable and can lose a water molecule (H₂O) as a leaving group. This results in the formation of a carbocation:
\[ \text{R-OH}_2^+ \rightarrow \text{R}^+ + \text{H}_2\text{O} \]
- The carbocation (R⁺) is a positively charged intermediate that is crucial in the dehydration process.

5. **Elimination to Form Alkene**:
- The final step involves the elimination of a proton (H⁺) from the carbocation, which leads to the formation of a double bond, resulting in the alkene:
\[ \text{R}^+ \rightarrow \text{Alkene} + \text{H}^+ \]

6. **Conclusion**:
- The intermediate species formed during the acid-catalyzed dehydration of alcohols is a **carbocation**.

### Final Answer:
The intermediate species formed is **carbocation**.