The monomers of buna-S rubber are

• A

  vinyl chloride and sulphur
• B

  butadiene
• Correct answer
  C

  styrene and butadiene
• D

  isoprene and butadiene

Solution

Buna-S rubber is also called SBR styrene -butadiene rubber. It is a copolymer of $75 \%$ butadiene $\left(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}=\mathrm{CH}_{2}\right)$ and $25 \%$ styrene $\left(\mathrm{C}_{6} \mathrm{H}_{5}-\mathrm{CH}=\mathrm{CH}_{2}\right)$.

Hence, the correct answer is option: 'C'.