Question

The monomers of Buna-S rubber are:
A.Vinyl chloride and sulphur
B.Butadiene
C.Styrene and butadiene
D.Isoprene and butadiene

Answer 1

Buna-S is a synthetic polymer made up from the combination of two monomer units. It is formed in the polymerization process at low temperature that’s why it is also called cold rubber. This rubber is also termed as styrene butadiene rubber (SBR).

Complete step by step answer:
Buna-S is a synthetic polymer made up from the combination of butadiene and styrene. It is a copolymer of $75\%$ butadiene and $25\%$ styrene.
Butadiene

Styrene

The polymerization reaction involved in the formation of Buna-S:

Buna-S is formed from the polymerization of butadiene and styrene in $1:3$. In this process peroxide is used as a catalyst at $5^\circ C$ therefore the formed product is also known as cold rubber. The vulcanization of this rubber is done with sulphur for better elasticity.
It has good resistance and long life stability when protected from additives.
They are used in manufacture of conveyor belts, shoe soles and electrical insulation.
Hence option (C) is correct, The monomers of Buna-S rubber are Styrene and butadiene.

Note:
Buna-S is called from different names such as cold rubber as it is manufactured under $5^\circ C$, styrene butadiene rubber (SBR) and 1-3,butadiene is IUPAC name of Buna-S.