When 2-methyl-2-butanol is heated with conc . `H_(2) SO_(4)` then main product formed is :

Options

A. 2-methyl-1-butene
B. 2-methyl-2-butene
C. Both (1) and (2)
D. None of these

Answer

To solve the problem of what product is formed when 2-methyl-2-butanol is heated with concentrated H₂SO₄, we can follow these steps:

### Step 1: Identify the Structure of 2-Methyl-2-butanol
2-methyl-2-butanol has the following structure:
- It is a branched alcohol with the formula C₅H₁₂O.
- The structure can be represented as:

```
CH3
|
CH3 - C - OH
|
CH2 - CH3
```

### Step 2: Understand the Reaction Conditions
When 2-methyl-2-butanol is heated with concentrated sulfuric acid (H₂SO₄), it undergoes dehydration. This means that a water molecule (H₂O) is removed from the alcohol, leading to the formation of an alkene.

### Step 3: Mechanism of Dehydration
The dehydration of alcohols typically follows an E1 mechanism:
- The hydroxyl group (OH) is protonated by the sulfuric acid, converting it into a better leaving group (water).
- The molecule then forms a carbocation. In this case, the carbocation formed is tertiary and is stabilized by hyperconjugation and inductive effects.

### Step 4: Identify the Carbocation
The carbocation formed from 2-methyl-2-butanol is:

```
CH3
|
CH3 - C⁺
|
CH2 - CH3
```

### Step 5: Determine the Beta Hydrogens
To form the alkene, we need to remove a beta hydrogen. The beta carbons are those adjacent to the carbocation. In this case, we have:
- Beta 1: CH3 (3 hydrogens)
- Beta 2: CH2 (2 hydrogens)

### Step 6: Apply the Zaitsev's Rule
According to Zaitsev's rule, the more substituted alkene is favored. Therefore, we will remove a hydrogen from the beta carbon that has fewer hydrogens (the CH2 group) to form the double bond.

### Step 7: Form the Alkene
When we remove a hydrogen from the CH2 group, we form the double bond between the carbocation and the beta carbon. The resulting alkene is:

```
CH3
|
CH3 - C = C - CH3
```

This compound is known as 2-methyl-2-butene.

### Final Answer
The main product formed when 2-methyl-2-butanol is heated with concentrated H₂SO₄ is **2-methyl-2-butene**.

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