Arrange the following compounds in order of ease of dehydrohalogenation by concentrated alcoholic KOH
A) `CH_(3)underset(CH_(3))underset(|)(C)HCH_(2)CH_(2)Br `
B)`CH_(3)CH_(2)underset(CH_(3))underset(|)overset(Br)overset(|)(C)CH_(3)`
C) `CH_(3)underset(CH_(3))underset(|)(C)Hoverset(Br)overset(|)(C)HCH_(3)`

Options

A. `CltBltA`
B. `AltBltC`
C. `BltCltA`
D. `BltAltC`

Answer

To solve the problem of arranging the compounds in order of ease of dehydrohalogenation by concentrated alcoholic KOH, we need to analyze the stability of the carbocations that would form during the reaction. The more stable the carbocation, the easier the dehydrohalogenation process will be.

### Step-by-Step Solution:

1. **Identify the Compounds**:
- A) `CH3-CH(CH3)-CH2-CH2Br` (1-bromo-2-methylbutane)
- B) `CH3-CH2-CH(CH3)-Br` (2-bromo-3-methylbutane)
- C) `CH3-CH(CH3)-C(CH3)-Br` (2-bromo-2-methylbutane)

2. **Determine the Type of Carbocation Formed**:
- For **Compound A**:
- When dehydrohalogenation occurs, the bond between the carbon attached to Br and the adjacent carbon breaks, forming a 1° carbocation.
- Stability: 1° (least stable).

- For **Compound B**:
- The bond between the carbon attached to Br and the adjacent carbon breaks, forming a 2° carbocation.
- Stability: 2° (more stable than 1°).

- For **Compound C**:
- The bond between the carbon attached to Br and the adjacent carbon breaks, forming a 3° carbocation.
- Stability: 3° (most stable).

3. **Rank the Stability of Carbocations**:
- The stability of carbocations is ranked as follows:
- 3° > 2° > 1°
- Therefore, the order of stability for the carbocations formed from the compounds is:
- C (3°) > B (2°) > A (1°)

4. **Order of Ease of Dehydrohalogenation**:
- Since the ease of dehydrohalogenation is directly related to the stability of the carbocation formed, we can conclude:
- C (most stable) > B > A (least stable)

5. **Final Arrangement**:
- The order of ease of dehydrohalogenation by concentrated alcoholic KOH is:
- **C > B > A**

### Final Answer:
The correct order is C, B, A.