A : `CH_(3)-underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-O-CH_(3)` on reaction with conc. Hl gives ` CH_(3) - underset(CH_(3))underset(|)overset(CH_(3))overset(|)(C)-l and CH_(3)OH` major product .
R : This reaction proceed by `S_(N)1` mechaism .

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 given question, we will break down the reaction and analyze the assertion and reason provided.

### Step-by-Step Solution:

1. **Identify the Compound**: The given compound is a symmetrical ether, specifically `CH3-CH(CH3)-O-CH3`. This can be represented as a tertiary ether because the carbon attached to the ether oxygen is bonded to three other carbon atoms.

2. **Reaction with Concentrated HI**: When this ether reacts with concentrated HI, the ether bond (C-O) will be cleaved. The concentrated acid (HI) will protonate the ether oxygen, making it a better leaving group.

3. **Formation of Carbocation**: The protonation of the ether oxygen leads to the formation of a good leaving group (water). When the ether bond breaks, it can lead to the formation of a tertiary carbocation. The ether bond cleavage will generate a tertiary carbocation and a methyl alcohol (CH3OH).

4. **Nucleophilic Attack**: The iodide ion (I-) from HI will then attack the carbocation formed. Since we have a tertiary carbocation, the iodide ion will preferentially attack this carbocation, leading to the formation of the major product, which is `CH3-CH(CH3)-I`.

5. **Major Products**: The major products of this reaction are `CH3-CH(CH3)-I` and `CH3OH`. The assertion states that the major product is `CH3-CH(CH3)-I` and `CH3OH`, which is correct.

6. **Mechanism**: The reason states that this reaction proceeds via an SN1 mechanism. In SN1 reactions, the rate-determining step involves the formation of a carbocation. Given that we have a stable tertiary carbocation, the reaction indeed follows an SN1 mechanism.

### Conclusion:
- **Assertion (A)**: True - The major products are indeed `CH3-CH(CH3)-I` and `CH3OH`.
- **Reason (R)**: True - The reaction proceeds via an SN1 mechanism due to the formation of a stable tertiary carbocation.

### Final Answer:
Both assertion and reason are true, and the reason correctly explains the assertion.

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