Question
Chemistry Question on introduction to organic chemistry
The number of σ bonds, π bonds and having pair of electrons in pyridine respectively.
A
12, 3, 0
B
11, 3, 1
C
12, 2, 1
D
11, 2, 0
Answer
11, 3, 1
Explanation
Solution
Pyridine has a chemical formula of C5H5N. The structure of pyridine consists of a ring of six carbon atoms and one nitrogen atom. Each carbon atom is bonded to two other carbon atoms and one hydrogen atom, and the nitrogen atom is bonded to one carbon atom and two hydrogen atoms. The nitrogen atom also possesses a lone pair of electrons. The aromatic ring has alternating single (σ) and double (π) bonds.
Counting the bonds and lone pairs:
- Carbon-carbon (C-C) single bonds: 5 (in the ring)
- Carbon-hydrogen (C-H) single bonds: 5 (one on each carbon)
- Carbon-nitrogen (C-N) single bond: 1
- Pi (π) bonds: 3 (these are part of the aromatic system)
- Lone pair of electrons on nitrogen: 1
Adding these up gives:
- Sigma (σ) bonds: 5 + 5 + 1 = 11
- Pi (π) bonds: 3
- Lone pair of electrons: 1
So, the correct option is (B): 11, 3, 1