Buna-S is the copolymer of 1,3-butadiene and styrene. The butadiene adds in the 1,4-manner, giving a −CH2−CH=CH−CH2− unit with a single internal double bond, and these alternate with styrene units −CH(C6H5)−CH2− that carry the phenyl group on a saturated carbon. The repeating structure built from −CH2−CH=CH−CH2− joined to −CH(C6H5)−CH2− correctly represents Buna-S.
JEE Main · 2023 · 10 Apr 2023 · Shift 2 · Single correct option
