Anti Markownikov addition takes place in which of the following reactions

Options

A. `CH_(3)CH=CH_(2)+HBr overset((C_(2)H_(5)CO)_(2)O_(2))to`
B. `CH_(2)=CH-CH_(2)Cl+HC l overset("Peroxide")to`
C. `CH_(3)=CH-CH_(2)OH+HC l overset("peroxide")to`
D. `CH_(3)=CH-CH_(2)CH_(2)CH_(2)CH_(2)OH+HC l overset("peroxide")to`

Answer

To determine which reaction exhibits anti-Markovnikov addition, we need to understand the concept of anti-Markovnikov addition and the conditions under which it occurs.

### Step-by-Step Solution:

1. **Understanding Anti-Markovnikov Addition**:
- Anti-Markovnikov addition refers to the addition of HX (where X is a halogen) to an alkene in such a way that the halogen atom (X) adds to the less substituted carbon atom of the double bond. This is contrary to Markovnikov's rule, which states that the more substituted carbon will receive the halogen.

2. **Identifying the Role of Peroxides**:
- Anti-Markovnikov addition typically occurs in the presence of peroxides (ROOR). The presence of peroxides leads to the formation of free radicals, which facilitates this type of addition.

3. **Analyzing the Given Reactions**:
- The question provides several reactions involving HBr, HCl, etc. We need to identify which of these reactions can undergo anti-Markovnikov addition.
- HBr in the presence of peroxides is known to follow anti-Markovnikov addition. This is because the peroxide initiates a free radical mechanism that results in the halogen (Br) adding to the less substituted carbon.

4. **Comparing with Other Halogen Acids**:
- In contrast, HCl does not typically undergo anti-Markovnikov addition because the bond between H and Cl is stronger, requiring more energy to break. Therefore, HCl does not favor the formation of free radicals necessary for anti-Markovnikov addition.

5. **Conclusion**:
- Based on the above analysis, the reaction that exhibits anti-Markovnikov addition is the one involving HBr in the presence of peroxides.

### Final Answer:
The reaction that exhibits anti-Markovnikov addition is the one involving **HBr in the presence of peroxides**.