question_answer

Natural rubber is a polymer of

A)  cis-isoprene

B)  trans-isoprene

C)  co-cis and trans isoprene

D)  None of the above

Correct Answer: A

Solution :

                 Natural rubber is a polymer of cis-isoprene. \[\underset{cis-isoprene}{\mathop{nC{{H}_{2}}=\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\mathop{C}}\,-CH-C{{H}_{2}}}}\,\xrightarrow{polymerisation}\] \[\underset{\begin{smallmatrix}  poly\text{ }cis\text{ }isoprene \\  (natural\text{ }rubber) \end{smallmatrix}}{\mathop{-\left( C{{H}_{2}}-\underset{\begin{smallmatrix}  | \\  C{{H}_{3}} \end{smallmatrix}}{\mathop{C}}\,=CH-C{{H}_{2}} \right)-}}\,\] Or