Question

The S in Buna-S refers to:
(A) Sulphur
(B) Styrene
(C) Sodium
(D) Just a trade name

Answer 1

Hint: Buna-S also known as styrene-butadiene or SBR (styrene-butadiene rubber), is the synthetic rubber derived from styrene and butadiene.
Buna-S is the name of a brand which was initially marketed by this name but now, SBR is more common.

Complete answer:
Let us see about this synthetic rubber;
Buna-S –
Buna-S (now, known as SBR) is the synthetic rubber produced from the monomers such as styrene and butadiene. It is the additional polymer. This is the commodity which competes with natural rubber in the market.
It has many applications such as sealing, binding, water-proofing and some building purposes. The former name of SBR was Buna-S which is derived from the prefixes of the constituent compounds.
In Buna-S, Bu stands for butadiene, Na stands for sodium and S stands for styrene i.e. Buna-S is the copolymer of buta 1, 3- diene and styrene in the ratio of 3:1 in the general presence of sodium.
The general appearance of SBR is,

Therefore, from the above discussion we can state that the S in Buna-S stands for styrene.

Hence, option (B) is correct.

Note:
Do note that the SBR is the replacement of the natural rubber. Also, we have every option initiating from letter ‘S’ so, do not get confused with those.
More confusion can occur in sodium and styrene, but do note that Na represents sodium and S represents styrene in the polymer.