Which of the following reaction is Anti-Markownikoff's addition ?

Options

A. `CH_(3)CH=CH_(2)+HBr overset("peroxide")to CH_(3)CHBr-CH_(3)`
B. `CH_(3)CH=CH_(2)+HBr overset("peroxide")to CH_(3)CH_(2)CH_(2)Br`
C. `CH_(3)CH=CH_(2)+HCl overset("peroxide")to CH_(3)CH_(2)CH_(2)Cl`
D. Both (B) and (C)

Answer

To determine which reaction represents an Anti-Markovnikov addition, we need to understand the concepts of Markovnikov's rule and Anti-Markovnikov's rule.

### Step-by-Step Solution:

1. **Understanding Markovnikov's Rule**:
- When HX (where X is a halogen) is added to an alkene, the hydrogen atom (H) will attach to the carbon atom that has more hydrogen atoms already attached. The halogen (X) will attach to the carbon atom with fewer hydrogen atoms.
- Example: In propene (CH3-CH=CH2) + HBr, H will add to the CH2 group (more hydrogens), and Br will add to the CH (fewer hydrogens), resulting in 2-bromopropane.

2. **Understanding Anti-Markovnikov's Rule**:
- In the presence of peroxides, the addition of HX to alkenes follows the Anti-Markovnikov rule. This means that the hydrogen atom will attach to the carbon with fewer hydrogen atoms, and the halogen will attach to the carbon with more hydrogen atoms.
- Example: In propene (CH3-CH=CH2) + HBr (with peroxide), H will add to the CH2 group (fewer hydrogens), and Br will add to the CH (more hydrogens), resulting in 1-bromopropane.

3. **Identifying the Reaction**:
- We need to analyze the given reactions to see which one involves the addition of HX (specifically HBr) in the presence of peroxides, leading to an Anti-Markovnikov product.
- If the reaction involves HBr and a peroxide, it will likely follow the Anti-Markovnikov rule.

4. **Evaluating Options**:
- **Option A**: If it involves HBr with peroxide, it is likely Anti-Markovnikov.
- **Option B**: If it involves HBr with peroxide and results in 1-bromopropane, this is Anti-Markovnikov.
- **Option C**: If it involves HCl, it will follow Markovnikov's rule regardless of peroxide presence.
- **Option D**: If both B and C are mentioned, and since C does not follow Anti-Markovnikov, this option is incorrect.

5. **Conclusion**:
- The correct answer is **Option B**, which represents the Anti-Markovnikov addition.