The compound CH$_3$CH(NH$_2$)CH$_2$CH$_2$CH$_3$ is an example of a

Analysis of the Question

The question asks us to classify an organic compound based on its functional group. Specifically, we need to determine the degree of the amine group attached to the carbon chain.

Concept Explanation

In organic chemistry, amines are classified as primary ($1^\circ$), secondary ($2^\circ$), or tertiary ($3^\circ$) based on the number of carbon groups (alkyl or aryl groups) directly attached to the nitrogen atom:

• Primary ($1^\circ$) amine: The nitrogen is attached to only one carbon atom (General formula: $R-NH_2$).
• Secondary ($2^\circ$) amine: The nitrogen is attached to two carbon atoms (General formula: $R_2NH$).
• Tertiary ($3^\circ$) amine: The nitrogen is attached to three carbon atoms (General formula: $R_3N$).

To classify the compound, we look at the nitrogen atom and count how many carbon atoms are directly bonded to it.

Step-by-Step Solution

1. Examine the structure: The compound is $CH_3-CH(NH_2)-CH_2-CH_2-CH_3$.
2. Identify the functional group: The functional group is the amino group ($-NH_2$) attached to the second carbon atom of the pentane chain.
3. Analyze the Nitrogen atom: • The nitrogen atom is bonded to two hydrogen atoms ($H_2$). • The nitrogen atom is bonded to exactly one carbon atom (the carbon at the second position of the chain).
4. Conclusion: Since the nitrogen is attached to only one alkyl group (a pentyl group), it is classified as a primary amine.

Note: Do not be confused by the fact that the carbon holding the nitrogen is a secondary carbon (a carbon attached to two other carbons). The classification of an amine depends solely on the number of carbons attached to the nitrogen, not the carbon holding the nitrogen.

Identifying the Answer

Based on the classification rules, the compound is a primary amine. This matches Option A.

Exam Tip

Always remember:

• Amines are classified by the number of carbons attached to the Nitrogen.
• Alcohols are classified by the number of carbons attached to the Carbon holding the $-OH$ group. Don't mix these two rules up in the exam hall!