Among the isomeric amines select the one with the lowest boiling point.

Options

A.
B.
C.
D.

Explanation

To determine which isomeric amine has the lowest boiling point, we need to consider the concept of hydrogen bonding and its influence on boiling points.

### Step-by-Step Solution:

1. **Understand the Structure of Isomeric Amines**:
Isomeric amines can have different structural arrangements (such as primary, secondary, and tertiary amines). The boiling point of these amines can vary based on their ability to form hydrogen bonds.

2. **Identify Hydrogen Bonding**:
Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (like nitrogen, oxygen, or fluorine) and is attracted to another electronegative atom. In amines, hydrogen bonding can occur between the hydrogen atoms attached to nitrogen and the lone pair of electrons on another nitrogen atom.

3. **Analyze Each Isomer**:
- **Primary Amines**: Typically have two hydrogen atoms available for bonding and can form strong hydrogen bonds.
- **Secondary Amines**: Have one hydrogen atom and can also form hydrogen bonds, but less effectively than primary amines.
- **Tertiary Amines**: Have no hydrogen atoms attached to nitrogen, which means they cannot form hydrogen bonds with other amines.

4. **Determine the Impact of Hydrogen Bonding on Boiling Point**:
- The stronger the hydrogen bonding, the higher the boiling point. Therefore, primary amines will generally have higher boiling points than secondary amines, which in turn will have higher boiling points than tertiary amines.

5. **Conclusion**:
Among the isomeric amines, the tertiary amine will have the lowest boiling point because it cannot participate in hydrogen bonding due to the absence of hydrogen atoms attached to the nitrogen atom.

### Final Answer:
The isomeric amine with the lowest boiling point is the **tertiary amine**.