Question

Buna-S is a polymer of:
$\left( A \right)$ Butadiene only
$\left( B \right)$ Butadiene and nitrile
$\left( C \right)$ Styrene only
$\left( D \right)$ Butadiene and styrene

Answer 1

Polymer is defined as the number of monomers linked or held together to form branches or longer change monomer units by repeating itself. It can be classified on the basis of low or high polymer density.

Complete step by step answer:
We know that a polymer is formed when one or more than one monomer units combine to give rise to a polymer for example when vinyl chloride (monomer) combines to form a polyvinyl chloride (polymer). If the same monomer units produce a polymer, this type of polymer is known as a homopolymer. If two different monomer units combine to give a polymer, this type of polymer is co-polymer.
Buna-S is an example of co-polymer because in Buna-s two different monomer units are combined (such as butadiene and styrene) to form Buna-S. Buna-s is formed by addition reaction between butadiene and styrene.
As we discussed above, Buna-S is a polymer if butadiene and styrene so the correct option is $\left( D \right)$ .

Additional information: Buna-S is a synthetic polymer, it has high abrasion resistance and high bearing capacity. In the presence of traces of ozone it gets oxidized. It is many used for manufacture of tires, shoes soles and wire and cable insulation.

Note:
It is to be noted that there is a polymer which is similar to Buna-S that is Buna-N. The main difference between Buna-S and Buna-N they contain different monomers. Buna-s consist of butadiene and styrene whereas Buna-N consist of butadiene and acrylonitrile. Buna-S has high tensile strength then Buna-N.