Explain the preparation of Nylon-$6$ and also write its uses.

What is a polymer? What can we say about the molecular mass of a polymer? In which four industries are polymers mostly used?

The polymer Buna-$S$ is made of .....

What are carbon fibers used for?

Which of the following statements are correct?
$(1)$ Biodegradable polymers can be converted into essential life substances after degradation.
$(2)$ Non-biodegradable polymers are active towards environmental processes.
$(3)$ Non-biodegradable polymers can be converted into essential life substances.
$(4)$ $PHBV$ is degraded by bacteria under environmental conditions.

Match the following List-$I$ (Monomer/s) with List-$II$ (Name of the polymer) and select the correct answer:
| List-$I$ (Monomer/s) | List-$II$ (Name of the polymer) |
| :--- | :--- |
| $A$. $CF_2=CF_2$ | $I$. Neoprene |
| $B$. $NH_2(CH_2)_6NH_2, HO_2C(CH_2)_4CO_2H$ | $II$. Bakelite |
| $C$. $C_6H_5OH, HCHO$ | $III$. Teflon |
| $D$. $CH_2=CH(Cl)-CH=CH_2$ | $IV$. Nylon $6, 6$ |