The order of basicity of amines in gaseous state is-

Options

A. `3^(@) gt 2^(@) gt NH_(3) gt 1^(@)`
B. `1^(@) gt 2^(@) gt 3^(@) gt NH_(3)`
C. `NH_(3) gt 1^(@) gt 2^(@) gt 3^(@)`
D. `3^(@) gt 2^(@) gt 1^(@) gt NH_(3)`.

Answer

To determine the order of basicity of amines in the gaseous state, we can follow these steps:

### Step 1: Understand Basicity
Basicity refers to the ability of a compound to accept protons (H⁺ ions). In the case of amines, the nitrogen atom has a lone pair of electrons that can be donated to a proton, making it a base.

### Step 2: Consider the Structure of Amines
Amines can be classified into three categories based on the number of alkyl groups attached to the nitrogen:
- Primary amines (1°) have one alkyl group.
- Secondary amines (2°) have two alkyl groups.
- Tertiary amines (3°) have three alkyl groups.

### Step 3: Analyze the Effect of Alkyl Groups
Alkyl groups are electron-donating due to the +I (inductive) effect. The more alkyl groups attached to the nitrogen, the more electron density is available on the nitrogen atom, which increases its ability to donate the lone pair and accept a proton.

### Step 4: Stability of Carbocations
The order of stability of carbocations is crucial because it correlates with the basicity of amines. The stability order is:
- Tertiary carbocation (3°) > Secondary carbocation (2°) > Primary carbocation (1°) > Ammonia (NH₃)

### Step 5: Establish the Order of Basicity
Since the basicity of amines in the gaseous state follows the same order as the stability of carbocations, we can conclude that the order of basicity for amines in the gaseous state is:
- Tertiary amines (3°) > Secondary amines (2°) > Primary amines (1°) > Ammonia (NH₃)

### Final Order of Basicity
Thus, the order of basicity of amines in the gaseous state is:
**3° > 2° > 1° > NH₃**