A compound (A) has molecular formula `C_(5)H_(9)CI` It does not react with bromine in `C CI_(4)` On treatment with a strong base it produces a single compound (B) (B) has a molecular formula `C_(5)H_(8)` and reacts with Baeyer's reagent . Reductive ozonotysis of (B) produces a compound (C ) which has a molecular formula `C_(5)H_(8) O_(2)`
formation of ( B) from (A) involves

Options

A. `S_(N)2` Mechanism
B. `E_(1)` mechanism
C. `E_(2)` Mechanism
D. 50% `E_(1)` and 50% `E_(2)` mechanism

Answer

To solve the problem step by step, we will analyze the information given about the compounds A, B, and C, and determine the mechanism involved in the formation of compound B from compound A.

### Step 1: Analyze Compound A
- **Given:** Compound A has the molecular formula C₅H₉Cl.
- **Hydrogen Deficiency:** To find the degree of unsaturation, we can replace Cl with CH₃ to get C₆H₁₂. The formula for an alkane is C₆H₁₄, which means there is one degree of unsaturation (1 pi bond or 1 ring).

### Step 2: Determine the Structure of Compound A
- Since compound A does not react with bromine in CCl₄, it indicates that it does not contain a double bond (alkene).
- Therefore, compound A must contain a ring structure (cycloalkane) with one chlorine atom.

### Step 3: Treatment with Strong Base
- When compound A is treated with a strong base, it produces compound B (C₅H₈).
- The reaction involves the elimination of HCl, which suggests that a hydrogen atom is removed from a beta carbon adjacent to the carbon bearing the chlorine atom.

### Step 4: Mechanism of Formation of Compound B
- The formation of compound B from compound A involves an elimination reaction.
- Since only one product is formed, this indicates a concerted mechanism.
- The strong base abstracts a beta hydrogen, and the bond shifts to eliminate the Cl atom, leading to the formation of compound B.

### Step 5: Identify the Type of Elimination Mechanism
- The elimination mechanism can be classified as either E1 or E2:
- **E1 Mechanism:** Involves the formation of a carbocation intermediate.
- **E2 Mechanism:** A concerted reaction where the base abstracts a hydrogen while the leaving group (Cl) departs simultaneously.

- Since we are forming a single product and there is no indication of a carbocation intermediate, the mechanism must be E2.

### Conclusion
The formation of compound B from compound A involves an E2 elimination mechanism.

### Final Answer
The correct answer is **E2 mechanism**.

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