Concept:Buna-N is a synthetic rubber with excellent oil resistance and mechanical strength, making it suitable for rubber belts.
Explanation:Rubber belts need a polymer that is elastic, tough, and resistant to oil and abrasion.
Buna-N, or nitrile rubber, is a copolymer of 1,3-butadiene (
CH2​=CH−CH=CH2​) and acrylonitrile (
CH2​=CH−CN).
It does not swell appreciably in oils and retains its flexibility, so it is widely used to make oil-resistant rubber belts, hoses, and gaskets.
Perspex is polymethyl methacrylate (PMMA), a transparent, rigid plastic used as a substitute for glass; it is not used for belts.
PVC (polyvinyl chloride) is used in pipes, wires, and flooring, but it lacks the elasticity required for rubber belts.
Polycarbonate is a strong, transparent engineering plastic used in safety helmets and CDs; it is not elastic like rubber.
Thus, the polymer used to obtain rubber belts is Buna-N.
Answer:Option A – Buna-N