The major product [B] in the following sequence of reaction is having how many `sp^3` hybridized Carbon atoms ?
` ``(CH_(3)-underset(CH(CH_3)_2)underset(|)C=CH-CH_2CH_3)underset((ii)H_2O_2,OH^(Theta))overset((i)B_2H_6)rarr[A]underset(Delta)overset("dil."H_2SO_4)rarr[B]`

Answer

To determine the number of sp³ hybridized carbon atoms in the major product [B] of the given reaction sequence, we will follow these steps:

### Step 1: Identify the starting material
The starting material is an alkene with the structure:
\[ \text{(CH}_3\text{)}_2\text{C}=\text{C}\text{H-CH}_2\text{CH}_3 \]

### Step 2: Understand the reaction sequence
The reaction involves two main steps:
1. Hydroboration-oxidation using diborane (B₂H₆) followed by hydrogen peroxide (H₂O₂) and hydroxide ion (OH⁻).
2. Treatment with dilute sulfuric acid (H₂SO₄) and heat.

### Step 3: Perform hydroboration-oxidation
In the hydroboration-oxidation step, the alkene undergoes reaction according to the anti-Markovnikov rule. This means that the hydroxyl group (OH) will attach to the less substituted carbon, while hydrogen will attach to the more substituted carbon.

- The product A formed will have the structure:
\[ \text{(CH}_3\text{)}_2\text{C(OH)-CH}_2\text{CH}_3 \]

### Step 4: Dehydration to form product B
When product A is treated with dilute sulfuric acid and heated, dehydration occurs. The hydroxyl group (OH) is protonated, leading to the formation of a carbocation. A hydride shift may occur to form a more stable tertiary carbocation, which can then lose water to form an alkene.

- The major product B will likely be:
\[ \text{(CH}_3\text{)}_2\text{C}=\text{C(CH}_3\text{)-CH}_2\text{CH}_3 \]

### Step 5: Count sp³ hybridized carbon atoms in product B
To find the number of sp³ hybridized carbon atoms in product B, we need to analyze its structure:
1. The carbon atoms involved in single bonds (sigma bonds) with four substituents are sp³ hybridized.
2. The carbon atoms involved in double bonds (like in alkenes) are sp² hybridized.

In the structure of product B:
- The two terminal CH₃ groups are sp³ hybridized.
- The CH₂ group adjacent to the double bond is also sp³ hybridized.
- The carbon atoms in the double bond (C=C) are sp² hybridized.

### Conclusion
In product B, the total number of sp³ hybridized carbon atoms is 4 (from the two CH₃ groups and the two CH₂ groups).

### Final Answer
The major product [B] has **4 sp³ hybridized carbon atoms**.

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