Iso -butylene can be converted into tert -butyl bromide by its reaction with

Options

A. HBr
B. `Br_(2)`
C. HBr in the presence of peroxides
D. HOBr

Answer

To convert isobutylene into tert-butyl bromide, we can follow these steps:

### Step 1: Identify the Reactants
Isobutylene (2-methylpropene) is the starting material. The reaction we are interested in is with hydrogen bromide (HBr).

### Step 2: Understand the Structure of Isobutylene
Isobutylene has the structure:
```
CH3
|
CH2=C
|
CH3
```
This structure indicates that isobutylene has a double bond between the second and third carbon atoms.

### Step 3: Reaction with HBr
When isobutylene reacts with HBr, the double bond opens up, and HBr adds across the double bond. The addition of HBr can occur in two ways:
1. The hydrogen (H) can add to the less substituted carbon (C2), leading to the formation of a more stable carbocation.
2. The bromine (Br) can add to the more substituted carbon (C3).

### Step 4: Formation of Carbocation
In this case, the hydrogen will add to the carbon with the least number of alkyl substituents (C2), resulting in the formation of a secondary carbocation on C3:
```
CH3
|
CH2-CH
|
Br
```
This secondary carbocation is more stable than a primary one.

### Step 5: Nucleophilic Attack
The bromide ion (Br-) will then attack the positively charged carbon (C3), leading to the formation of tert-butyl bromide:
```
CH3
|
CH3-C
|
Br
```
This structure represents tert-butyl bromide, which is the desired product.

### Step 6: Conclusion
Thus, the reaction of isobutylene with HBr results in the formation of tert-butyl bromide.

### Final Answer
Isobutylene can be converted into tert-butyl bromide by its reaction with hydrogen bromide (HBr).

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