`CH_3CH_2-CH=CH_2+HBr overset"ROOR"to underset"Major"[X]+underset"Minor"[Y]`
[X] and [Y] respectively are

Options

A. `BrCH_2CH_2CH=CH_2` and `C_2H_5-CHBr-CH_3`
B. `C_2H_5-CH_2CH_2-Br` and `Br-CH_2CH_2-CH=CH_2`
C. `C_2H_5-CH_2-CH_2Br` and `C_2H_5-CHBr -CH_3`
D. `C_2H_5CHBr-CH_3` and `C_2H_5-CH_2-CH_2Br`

Explanation

To solve the problem involving the reaction of 1-butene (CH3CH2-CH=CH2) with HBr in the presence of peroxides, we will follow these steps:

### Step 1: Identify the Reaction Type
The reaction of alkenes with HBr in the presence of peroxides is a free radical addition reaction. This process is known to follow the anti-Markovnikov's rule, where the bromine atom will attach to the less substituted carbon atom of the alkene.

**Hint:** Remember that in free radical reactions, the stability of the free radical intermediate plays a crucial role in determining the major and minor products.

### Step 2: Draw the Structure of 1-Butene
The structure of 1-butene is:
```
H H H
| | |
H--C--C=C--C--H
| | |
H H H
```

### Step 3: Identify the Free Radical Formation
In the presence of peroxides, the HBr will generate free radicals. The bromine radical (Br•) will add to the less substituted carbon of the double bond, leading to the formation of a free radical on the more substituted carbon.

**Hint:** Identify which carbon atom has more hydrogen atoms attached to it; this will help you determine where the bromine will add.

### Step 4: Determine the Major and Minor Products
1. **Major Product (X):** The bromine will add to the terminal carbon (C1), resulting in a more stable secondary free radical on C2. The product will be:
- CH3-CH2-CH(Br)-CH3 (2-bromobutane)

2. **Minor Product (Y):** The bromine will add to the more substituted carbon (C2), resulting in a less stable primary free radical on C1. The product will be:
- CH2(Br)-CH2-CH2-CH3 (1-bromobutane)

**Hint:** The major product is typically the one formed from the more stable free radical, while the minor product is from the less stable radical.

### Step 5: Write the Final Products
- **Major Product (X):** 2-bromobutane (CH3-CH2-CH(Br)-CH3)
- **Minor Product (Y):** 1-bromobutane (CH2(Br)-CH2-CH2-CH3)

### Conclusion
Thus, the final answers are:
- [X] = 2-bromobutane
- [Y] = 1-bromobutane