A : `CH_(3) - underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-CH=CH_(2)` on hydroboration oxidation gives `CH_(3)-underset(OH)underset(|)overset(CH_(3))overset(|)(C)-underset(CH_(3))underset(|)(CH)-CH_(3)` as major product .
R : It involves the formation of carbocation so undergoes rearrangement .

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion, then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion, then mark (2)
C. If Assertion is true statement but Reason is false , then mark (3)
D. If both Assertion and Reason are false statements , then mark (4)

Answer

To solve the assertion-reason question, we need to analyze both the assertion (A) and the reason (R) step by step.

### Step 1: Understanding the Assertion (A)
The assertion states that the hydroboration-oxidation of the given alkene results in a specific major product. The alkene is represented as:
\[ \text{CH}_3 - \text{C}(\text{CH}_3) - \text{C}(\text{CH}_3) = \text{CH}_2 \]
Upon hydroboration-oxidation, it yields:
\[ \text{CH}_3 - \text{C}(\text{OH}) - \text{C}(\text{CH}_3) - \text{C}(\text{CH}_3) \]

### Step 2: Hydroboration-Oxidation Mechanism
1. **Hydroboration**: In this step, BH3 (borane) is added to the alkene in the presence of tetrahydrofuran (THF). The double bond attacks the boron, leading to the formation of a trialkylborane intermediate.
2. **Oxidation**: The trialkylborane is then oxidized using NaOH and H2O2, resulting in the formation of an alcohol.

### Step 3: Analyzing the Product
The product formed is an alcohol where the hydroxyl group (OH) is added to the more substituted carbon atom, which is consistent with Markovnikov's rule. The assertion claims that this product is the major product, which is indeed correct.

### Step 4: Understanding the Reason (R)
The reason states that a carbocation is formed during the reaction, which undergoes rearrangement. However, in hydroboration-oxidation, the mechanism does not involve a carbocation intermediate. Instead, it proceeds through a concerted mechanism where the boron adds to the alkene without forming a stable carbocation.

### Step 5: Conclusion
- **Assertion (A)**: True (the major product is correctly identified).
- **Reason (R)**: False (there is no carbocation formed in this reaction).

### Final Answer
The assertion is true, but the reason is false. Therefore, the correct conclusion is that the reason does not correctly explain the assertion.

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