Which from following is NOT true about natural rubber?
Which from following is NOT true about natural rubber?
It is formed by addition polymerization.
It is a linear polymer.
It has cis configuration of $\mathrm{C}=\mathrm{C}$.
It contains butadine and styrene as monomer units.
Solution
1. It is formed by addition polymerization
- Natural rubber is formed by the addition polymerization of isoprene units. This is correct.
2. It is a linear polymer
- Natural rubber is primarily a linear polymer of isoprene, although it may have a slight degree of branching. This is correct.
3. It has cis configuration of $\mathrm{C}=\mathrm{C}$
- Natural rubber has cis-1,4-polyisoprene as its primary structure, which gives it elasticity. This is correct.
4. It contains butadiene and styrene as monomer units
- This is incorrect. Butadiene and styrene are the monomers of synthetic rubber known as styrene-butadiene rubber (SBR), not natural rubber. Natural rubber contains isoprene as its monomer.