How many amines are possible with the molecular formula
`C_(4)H_(11)N` (structural isomers only) :-

Options

A. 6
B. 7
C. 8
D. 9

Answer

To determine how many structural isomers of amines are possible with the molecular formula C₄H₁₁N, we will systematically identify each unique structure based on the arrangement of carbon atoms and the placement of the amine group (NH₂, NH, or N).

### Step-by-Step Solution:

1. **Identify the Base Structure**:
The molecular formula C₄H₁₁N indicates that we have 4 carbon atoms, 11 hydrogen atoms, and 1 nitrogen atom. The amine group can be primary (NH₂), secondary (NH), or tertiary (N).

2. **Draw the Primary Amines**:
- **Butane-1-amine**: This is the straight-chain structure where the amine group is at the end.
- Structure: CH₃-CH₂-CH₂-CH₂-NH₂
- **2-Methylpropane-1-amine**: A branched structure with the amine group at the end.
- Structure: CH₃-CH(CH₃)-CH₂-NH₂
- **Butane-2-amine**: A structure where the amine group is on the second carbon.
- Structure: CH₃-CH(CH₃)-CH₂-NH₂

3. **Draw the Secondary Amines**:
- **N-Ethyl ethanamine**: The amine group is bonded to two carbon chains.
- Structure: CH₃-CH₂-NH-CH₂-CH₃
- **N-Methylpropane-1-amine**: The amine group is bonded to one carbon chain and one methyl group.
- Structure: CH₃-CH₂-CH(NH)-CH₃
- **N-Methylpropane-2-amine**: The amine group is bonded to a carbon chain with a methyl group.
- Structure: CH₃-CH(NH)-CH₃-CH₃

4. **Draw the Tertiary Amines**:
- **N,N-Dimethylethanamine**: The nitrogen is bonded to two methyl groups and one ethyl group.
- Structure: (CH₃)₂N-CH₂-CH₃
- **N,N-Dimethylpropane-1-amine**: The nitrogen is bonded to three carbon chains.
- Structure: (CH₃)₂N-CH₂-CH₂-CH₃

5. **Count the Isomers**:
After drawing all possible structures, we can count the unique structural isomers:
- Primary Amines: 3
- Secondary Amines: 3
- Tertiary Amines: 2

Total = 3 (primary) + 3 (secondary) + 2 (tertiary) = 8 structural isomers.

### Final Answer:
There are **8 structural isomers** possible for the molecular formula C₄H₁₁N.

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