Acid catalysed dehydration of t-butanol is faster than that of n-butanol because

Options

A. tertiary carbocation is more stable than primary carbocation
B. primary carbocation is more stable than tertiary carbocation
C. t-butanol has a higher boiling point
D. rearrangement takes place during dehydration of t-butanol.

Answer

To understand why the acid-catalyzed dehydration of t-butanol is faster than that of n-butanol, we need to analyze the mechanism of the reaction and the stability of the carbocations involved.

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The two alcohols in question are t-butanol (tert-butanol) and n-butanol (normal butanol).
- Tert-butanol has the structure (CH₃)₃COH, while n-butanol has the structure CH₃CH₂CH₂OH.

2. **Understand the Reaction Conditions**:
- The dehydration of alcohols is typically carried out using a strong acid, such as concentrated sulfuric acid (H₂SO₄).
- This acid protonates the hydroxyl group (-OH) of the alcohol, making it a better leaving group.

3. **Formation of Carbocations**:
- When t-butanol is treated with H₂SO₄, the protonation of the hydroxyl group leads to the formation of a tertiary carbocation (C⁺), which is highly stable due to hyperconjugation and inductive effects from the surrounding alkyl groups.
- Conversely, when n-butanol undergoes the same reaction, it forms a primary carbocation, which is less stable because it has fewer alkyl groups to stabilize the positive charge.

4. **Stability of Carbocations**:
- Carbocation stability follows the order: tertiary > secondary > primary.
- The tertiary carbocation formed from t-butanol is more stable than the primary carbocation formed from n-butanol.

5. **Rate of Reaction**:
- The rate of the dehydration reaction is directly related to the stability of the carbocation formed. A more stable carbocation will lead to a faster reaction.
- Therefore, since the tertiary carbocation is more stable than the primary carbocation, the dehydration of t-butanol occurs at a faster rate than that of n-butanol.

6. **Conclusion**:
- The correct answer to the question is that the dehydration of t-butanol is faster than that of n-butanol because the tertiary carbocation is more stable than the primary carbocation.