Question

Nicotine is an addictive substance found in tobacco. Identify the hybridization state and geometry of each of the nitrogen atoms in nicotine:

Answer 1

The hybridization state and geometry of the nitrogen atoms in nicotine are sp2 and trigonal planar with a bond angle of approximately 120 degrees.

Step-by-step explanation:

The hybridization state and geometry of each of the nitrogen atoms in nicotine can be determined using the VSEPR theory which is based on the idea that electron pairs in the valence shell of an atom repel each other. Nicotine contains two nitrogen atoms.

The first nitrogen atom in nicotine is located in the pyrrolidine ring and is sp2 hybridized. It has a trigonal planar geometry with a bond angle of approximately 120 degrees.

The second nitrogen atom in nicotine is in the pyridine ring and is also sp2 hybridized. It has a trigonal planar geometry with a bond angle of approximately 120 degrees.

Answer 2

The structure of nicotine is as follows:

In the aromatic ring, nitrogen atom has two bonds and one lone pair therefore, hybridization will be
`sp^(2)`. In five-membered ring , nitrogen has two bonds and 1 lone pair therefore, hybridization will be
`sp^(3)`.

Therefore, hybridization state of
`N^(1)` and
`N^(2)` (as in the attached structure) is
`sp^(2)` and
`sp^(3)` respectively.

Now, according to VESPR theory for
`sp^(2)` hybridization with one lone pair the geometry is bent and for
`sp^(3)` hybridization with one lone pair the geometry is pyramidal.

Therefore, geometry of
`N^(1)` and
`N^(2)` (as in the attached structure) is bent and pyramidal respectively.