Assertion : Tert- butyl methyl ether on cleavage with HI at 373 K gives tert-bytyl iodide and methano.
Reason : The reaction occurs by `S_(N^(1))` mechanism.

Options

A. If both assertion and reason are correct and reason is correct explanation for assertion.
B. If both assertion and reason are correct but reason is not correct for assertion.
C. If assertion is correct but reason is incorrect.
D. If both assertion and reason are incorrect.

Explanation

To solve the question, we will analyze the assertion and the reason step by step.

### Step 1: Understand the Assertion
The assertion states that tert-butyl methyl ether reacts with HI at 373 K to produce tert-butyl iodide and methanol.

- **Tert-butyl methyl ether** has the structure:
\[ (CH_3)_3C-O-CH_3 \]
- When it reacts with HI, we expect it to undergo cleavage.

### Step 2: Reaction Mechanism
The reaction of ethers with hydrogen halides typically involves protonation of the ether oxygen, leading to the formation of an oxonium ion.

- In this case, the ether oxygen gets protonated by HI, forming a protonated ether (oxonium ion):
\[ (CH_3)_3C-O^+H_2 \]

### Step 3: Formation of Carbocation
Following protonation, the bond between the oxygen and the tert-butyl group can break, leading to the formation of a carbocation and methanol.

- The cleavage results in:
\[ (CH_3)_3C^+ + CH_3OH \]
- Here, the tert-butyl carbocation \((CH_3)_3C^+\) is formed, which is a stable tertiary carbocation.

### Step 4: Nucleophilic Attack
The iodide ion (\(I^-\)) from HI can now act as a nucleophile and attack the carbocation to form tert-butyl iodide.

- The final products are:
\[ (CH_3)_3C-I + CH_3OH \]

### Step 5: Mechanism Type
The reaction proceeds via an \(S_N1\) mechanism because:
- It involves the formation of a carbocation intermediate.
- The rate-determining step is the formation of the carbocation, which is characteristic of \(S_N1\) reactions.

### Conclusion
Both the assertion and the reason are correct:
- The assertion is correct because tert-butyl methyl ether does yield tert-butyl iodide and methanol upon reaction with HI.
- The reason is also correct as the reaction occurs via an \(S_N1\) mechanism, which explains the formation of the carbocation.

### Final Answer
Both the assertion and reason are correct, and the reason is the correct explanation for the assertion.

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