Which one of the following is a copolymer ?

Options

A. Buna - S
B. Polyvinyl chloride
C. Polypropylene
D. Poly - cis - isoprene

Answer

To determine which of the given options is a copolymer, we need to understand what a copolymer is. A copolymer is a polymer that is made from two different types of monomer units.

Let's analyze the options provided:

1. **Buona S**: This polymer is made from two different monomers: butadiene and styrene. Since it is composed of two different monomer units, it qualifies as a copolymer.

2. **Polyvinyl Chloride (PVC)**: The monomer for PVC is vinyl chloride. Since it is made from only one type of monomer, it is not a copolymer.

3. **Polypropylene**: The monomer unit for polypropylene is propylene. Like PVC, it is made from only one type of monomer, so it is not a copolymer.

4. **Polycis Isoprene**: This polymer is made from the monomer cis-1,4-isoprene. Since it also consists of only one type of monomer, it is not a copolymer.

From this analysis, we can conclude that the only copolymer among the options is Buona S, which is made from butadiene and styrene.

**Final Answer**: Buona S is a copolymer.