Monobrominaton of 2-methylbutane gives how many distinct isomers ?

Options

A. One
B. Two
C. three
D. four

Answer

To determine the number of distinct isomers formed from the monobromination of 2-methylbutane, we can follow these steps:

### Step 1: Understand the structure of 2-methylbutane
2-methylbutane is an alkane with the following structure:
- It has a straight chain of 4 carbon atoms (butane) with a methyl group (CH3) attached to the second carbon.
- The molecular formula is C5H12.

### Step 2: Identify possible positions for bromination
In monobromination, a bromine atom (Br) replaces one hydrogen atom (H) in the alkane. The bromination can occur at different positions on the carbon chain. The possible positions for bromination in 2-methylbutane are:
1. At the terminal carbon (C1)
2. At the second carbon (C2)
3. At the third carbon (C3)
4. At the fourth carbon (C4)

### Step 3: Draw the structures of the isomers
Now, we will draw the structures for each of the positions where bromination can occur:

1. **Bromination at C1**:
- Structure: Br-CH2-CH(CH3)-CH2-CH3
- This gives us 1-bromo-2-methylbutane.

2. **Bromination at C2**:
- Structure: CH3-CH(Br)-CH(CH3)-CH3
- This gives us 2-bromo-2-methylbutane.

3. **Bromination at C3**:
- Structure: CH3-CH2-CH(Br)-CH3
- This gives us 3-bromo-2-methylbutane.

4. **Bromination at C4**:
- Structure: CH3-CH2-CH2-CH(Br)-CH3
- This gives us 4-bromo-2-methylbutane.

### Step 4: Count the distinct isomers
From the above structures, we can see that we have the following distinct isomers:
1. 1-bromo-2-methylbutane
2. 2-bromo-2-methylbutane
3. 3-bromo-2-methylbutane
4. 4-bromo-2-methylbutane

Thus, the total number of distinct isomers formed from the monobromination of 2-methylbutane is **4**.

### Final Answer
The answer is **4 distinct isomers**.

---