Q.13. - Organic Chemistry

Question

Question: (a) How is each N atom in quinine, an effective antimalarial drug that reduces fever, hybridized? (b) In what type of orbital does the lone pair on each N reside?

Step-by-Step Solution

Answer

Answer 

a. Hybridization of each N atom is as follows:

 

At 1:  $s{p}^3$ hybridized

At 2: $s{p}^2$ hybridized

b. The lone pair resides in the following position:

 

At 1:  $s{p}^3$ hybrid orbital

At 2: $s{p}^2$  hybrid orbital

Step 1: Lone pair

The heterocycles have at least one pair of non-bonding electrons, i.e., lone pairs.

Depending upon the type of bond, these lone pairs can be part of aromatic rings and will be involved in delocalization or cannot be involved in delocalization.

Step 2: Hybridization and orbitals

                                Quinine 

 

At 1: N atom is attached to four groups (three atoms and one lone pair).Therefore, it is $s{p}^3$  hybridized. The lone pair is not involved in delocalization and resides in a $s{p}^3$ hybrid orbital.

 

At 2: N atom is attached to three groups (two atoms and one lone pair).Therefore, it is $s{p}^2$ hybridized. The lone pair is not part of the aromatic ring and resides in a $s{p}^2$ hybrid orbital.