Which of the following compounds give most stable carbonium ion on dehydration?

Options

A. `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-OH`
B. `CH_(3)-underset(CH_(3))underset(|)(CH)-CH_(2)OH`
C. `CH_(3)-underset(OH)underset(|)(CH)-CH_(2)-CH_(3)`
D. `CH_(3)CH_(2)CH_(2)CH_(2)OH`

Answer

To determine which compound gives the most stable carbonium ion upon dehydration, we need to analyze the stability of the carbonium ions formed from each compound. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
List the compounds provided in the question. For this explanation, let's assume we have four compounds labeled A, B, C, and D.

### Step 2: Analyze Dehydration Products
For each compound, determine the type of carbonium ion (carbocation) that is formed upon dehydration:
- **Compound A**: Forms a tertiary carbocation (3°).
- **Compound B**: Forms a primary carbocation (1°).
- **Compound C**: Forms a secondary carbocation (2°).
- **Compound D**: Forms a primary carbocation (1°).

### Step 3: Determine Stability of Carbocations
Recall the stability order of carbocations:
- Tertiary (3°) > Secondary (2°) > Primary (1°)
This means that tertiary carbocations are the most stable due to hyperconjugation and inductive effects.

### Step 4: Compare the Stability
From the analysis:
- Compound A yields a tertiary carbocation, which is the most stable.
- Compound B and Compound D yield primary carbocations, which are the least stable.
- Compound C yields a secondary carbocation, which is more stable than primary but less stable than tertiary.

### Step 5: Conclusion
Since Compound A forms the most stable tertiary carbocation upon dehydration, it is the correct answer.

### Final Answer
The compound that gives the most stable carbonium ion upon dehydration is **Compound A**.

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