Identify the monomer units involved in the formation of $\text{Buna-N}$ rubber.

Solution

1. $\text{Buna-N}$ is a synthetic rubber known as nitrile rubber.
2. It is produced by the copolymerization of $\text{1,3-butadiene}$ and $\text{acrylonitrile}$ ($\text{vinyl cyanide}$).
3. $\text{Buna-S}$ is the copolymer of $\text{1,3-butadiene}$ and $\text{styrene}$.
4. Hence the answer is (B).