Find out the total number of major products (including stereoisomers) are obtained in each of the following reactions.
(a) 1-butene `+ HCl rarrx`
(b) 1-butene `+ HBr +` peroxide `rarry`
Find the value of `(x + y)` ?

Answer

To solve the problem, we need to analyze the two reactions involving 1-butene and determine the total number of major products, including stereoisomers.

### Step-by-Step Solution:

**(a) Reaction of 1-butene with HCl:**

1. **Identify the structure of 1-butene:**
1-butene has the structure: CH2=CH-CH2-CH3.

2. **Mechanism of the reaction:**
When 1-butene reacts with HCl, the H+ from HCl will add to the less substituted carbon (Markovnikov's rule), leading to the formation of a secondary carbocation.

3. **Formation of products:**
The Cl- ion will then attack the carbocation, leading to the formation of two possible products:
- 2-chlorobutane (from the secondary carbocation).
- 1-chlorobutane (from the less stable primary carbocation, which is a minor product).

4. **Stereoisomers:**
For 2-chlorobutane, there are two stereoisomers (R and S forms) due to the presence of a chiral center.

5. **Total products from this reaction:**
- 1-chlorobutane (1 product)
- 2-chlorobutane (2 stereoisomers)
- Total = 1 + 2 = 3 products.

**(b) Reaction of 1-butene with HBr in the presence of peroxide:**

1. **Mechanism of the reaction:**
In the presence of peroxide, the addition of HBr follows the anti-Markovnikov rule due to the formation of free radicals. The H radical adds to the less substituted carbon.

2. **Formation of products:**
The Br radical will then add to the carbon that is now a free radical, leading to the formation of:
- 1-bromobutane (major product).

3. **Stereoisomers:**
There are no stereoisomers for 1-bromobutane as there is no chiral center.

4. **Total products from this reaction:**
- 1-bromobutane (1 product).
- Total = 1 product.

### Final Calculation:

Now, we combine the total number of products from both reactions:

- From (a): 3 products (1-chlorobutane + 2 stereoisomers of 2-chlorobutane)
- From (b): 1 product (1-bromobutane)

Thus, \( x + y = 3 + 1 = 4 \).

### Answer:
The value of \( (x + y) \) is **4**.