A : The reaction between benzene and `(CH_(3))_(3)C.COCl` in the presence of anhyd `AICI_(3)` gives ter-butyl benzene as major product.
R : `(CH_(3))_(3)C.overset(o+)CO` is formed first which converted into more stable `(CH_(3))_(3)C^(o+)` by libérating CO.

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 problem, we will analyze the assertion and reason provided in the question step by step.

### Step 1: Understand the Reaction
The reaction involves benzene and tert-butyl carbonyl chloride `(CH₃)₃C.COCl` in the presence of anhydrous aluminum chloride (AlCl₃).

### Step 2: Identify the Role of AlCl₃
AlCl₃ acts as a Lewis acid, which means it can accept electrons. In this reaction, it will coordinate with the chlorine atom of the carbonyl chloride, facilitating the formation of a carbocation.

### Step 3: Formation of the Initial Carbocation
When `(CH₃)₃C.COCl` reacts with AlCl₃, the chlorine atom is removed, leading to the formation of a carbonyl cation `(CH₃)₃C^+.CO`. This initial carbocation is not stable due to the presence of the carbonyl group.

### Step 4: Rearrangement to a More Stable Carbocation
The unstable carbocation `(CH₃)₃C^+.CO` can lose carbon monoxide (CO) to form a more stable tert-butyl carbocation `(CH₃)₃C^+`. This is a tertiary carbocation, which is more stable due to hyperconjugation and inductive effects from the three methyl groups.

### Step 5: Electrophilic Attack on Benzene
The stable tert-butyl carbocation `(CH₃)₃C^+` can now act as an electrophile and attack the benzene ring. The positive charge on the carbocation will interact with the π electrons of the benzene, leading to the formation of a new carbon-carbon bond.

### Step 6: Formation of Tertiary Butyl Benzene
After the electrophilic attack, the benzene ring will lose a hydrogen atom (which will be released as H⁺), resulting in the formation of tert-butyl benzene as the major product.

### Conclusion
Thus, the assertion is true because the reaction produces tert-butyl benzene as the major product. The reason is also true, as the initial carbocation indeed rearranges to a more stable tertiary carbocation before reacting with benzene.

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

---