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 question regarding the main product formed when 2-methyl-2-butanol is heated with concentrated sulfuric acid (H₂SO₄), we can follow these steps:

### Step 1: Identify the Structure of 2-methyl-2-butanol
2-methyl-2-butanol is a branched alcohol with the following structure:
- It has four carbon atoms in the main chain (butanol).
- There is a methyl group attached to the second carbon.
- The hydroxyl (OH) group is also on the second carbon.

The structure can be represented as:
```
CH3
|
CH3 - C - OH
|
CH2 - CH3
```

### Step 2: Understand the Reaction with Concentrated H₂SO₄
When 2-methyl-2-butanol is heated with concentrated sulfuric acid, dehydration occurs. Concentrated sulfuric acid acts as a dehydrating agent, promoting the elimination of water (H₂O) from the alcohol.

### Step 3: Formation of Carbocation
Upon heating, the hydroxyl group (OH) is protonated by sulfuric acid, making it a better leaving group. The water molecule then leaves, resulting in the formation of a carbocation. In this case, a tertiary carbocation is formed because the positive charge is on a carbon that is attached to three other carbon atoms.

### Step 4: Elimination of a Proton
The next step involves the elimination of a proton (H⁺) from one of the adjacent carbon atoms to the carbocation, leading to the formation of a double bond. Since the carbocation is tertiary, it is stable, and the elimination can occur from either of the two adjacent carbon atoms.

### Step 5: Identify the Alkene Products
The elimination can lead to the formation of two possible alkenes:
1. If the H⁺ is removed from the carbon adjacent to the carbocation that has a methyl group, we get 2-methyl-2-butene.
2. If the H⁺ is removed from the other adjacent carbon, we also get 2-methyl-2-butene.

Both pathways yield the same alkene product, which is 2-methyl-2-butene.

### Step 6: Determine the Major Product
Since both pathways lead to the same product, the main product formed from the reaction of 2-methyl-2-butanol with concentrated sulfuric acid is 2-methyl-2-butene. This alkene is more stable due to the presence of more alpha hydrogens compared to any other possible products.

### Final Answer
The main product formed is **2-methyl-2-butene**.

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