Total number of isomeric products(excluding stereoisomers) formed on monochlorination of 2-methylbutane are

Options

A. 3
B. 4
C. 5
D. 2

Answer

To determine the total number of isomeric products (excluding stereoisomers) formed on the monochlorination of 2-methylbutane, we can follow these steps:

### Step 1: Draw the structure of 2-methylbutane
2-methylbutane has the following structure:
```
CH3
|
CH3-CH-CH2-CH3
|
CH3
```
This structure indicates that 2-methylbutane has a branched alkane with a total of 5 carbon atoms.

### Step 2: Identify the types of hydrogen atoms
In the structure of 2-methylbutane, we can identify the different types of hydrogen atoms based on their carbon environments:
- **Tertiary (3°) hydrogens**: There is 1 carbon with 3 hydrogens attached (the carbon in the middle of the chain).
- **Secondary (2°) hydrogens**: There are 2 carbons with 2 hydrogens attached (the two carbons adjacent to the tertiary carbon).
- **Primary (1°) hydrogens**: There are 6 terminal hydrogens (the two terminal carbons).

### Step 3: Count the unique products from monochlorination
Monochlorination replaces one hydrogen atom with a chlorine atom. Each type of hydrogen substitution will yield a different isomer:
1. **Substituting a tertiary hydrogen** will yield one unique product.
2. **Substituting a secondary hydrogen** will yield a different unique product.
3. **Substituting one of the primary hydrogens** will yield a unique product as well.

### Step 4: Identify the unique isomeric products
- **From tertiary hydrogen substitution**: 1 unique product.
- **From secondary hydrogen substitution**: 2 unique products (since there are two secondary hydrogens).
- **From primary hydrogen substitution**: 1 unique product.

### Step 5: Total the unique products
Adding these together:
- 1 (from tertiary) + 2 (from secondary) + 1 (from primary) = 4 unique isomeric products.

### Conclusion
The total number of isomeric products (excluding stereoisomers) formed on the monochlorination of 2-methylbutane is **4**.

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