In acid catalysed hydration of alkenes, reaction intermediate formed is

Options

A. Free radical
B. Carbocation
C. Carbanion
D. Carbene

Answer

To determine the reaction intermediate formed in the acid-catalyzed hydration of alkenes, we can follow these steps:

### Step 1: Understand the Reaction Mechanism
In acid-catalyzed hydration, an alkene reacts with water in the presence of an acid catalyst. The general mechanism involves the protonation of the alkene to form a carbocation.

**Hint:** Remember that the first step in many electrophilic addition reactions involves the formation of a carbocation.

### Step 2: Protonation of the Alkene
The alkene (RCH=CH2) reacts with a proton (H+) from the acid, leading to the formation of a carbocation. This occurs because the double bond of the alkene acts as a nucleophile and attacks the proton.

**Hint:** Identify the site of protonation on the alkene; it will typically occur at the less substituted carbon to form the most stable carbocation.

### Step 3: Formation of the Carbocation
Once the alkene is protonated, a carbocation intermediate is formed. The stability of this carbocation can vary depending on the structure of the alkene (primary, secondary, or tertiary).

**Hint:** Consider the stability of carbocations; tertiary carbocations are more stable than secondary, which are more stable than primary.

### Step 4: Nucleophilic Attack by Water
After the carbocation is formed, water (acting as a nucleophile) attacks the positively charged carbon atom of the carbocation, leading to the formation of an oxonium ion (a protonated alcohol).

**Hint:** Remember that water is a weak nucleophile but can effectively attack the carbocation due to its positive charge.

### Step 5: Deprotonation
Finally, the oxonium ion loses a proton (H+) to yield the final alcohol product. This step regenerates the acid catalyst.

**Hint:** Look for the loss of a proton to convert the oxonium ion into a neutral alcohol.

### Conclusion
The reaction intermediate formed in the acid-catalyzed hydration of alkenes is a **carbocation**.