When carbon bonds in organic compounds, which of the following are true:

Carbon makes $4$ bonds.

Carbon can form single, double or triple bonds.

Carbon atoms can form branched chains.

Carbon forms covalent bonds.

All of these are true.

Which of the following statements is NOT correct?

In thermoplastics, the molecular chains are not cross$-$linked, the macromolecules are mainly located next to each other.

Thermosets do not soften due to their strong covalent crosslinks and also offer a better dimensional stability than thermoplastics.

Thermosets have no chemical bonds, but intermolecular forces that connect the chains that allow them to have better dimensional stability.

Elastomers share the properties of both thermosets and thermoplastics.

Elastomers, unlike thermosets, form covalent crosslink networks.

Which of the following statements about rubber is false?

Natural rubber is obtained from the sap of the rubber tree.

Vulcanization uses sulfur to prevent heated rubber from becoming sticky.

It is not possible to make synthetic rubber.

The sap of the rubber tree is called latex.

Zinc oxide is a common filler used in rubber to increase durability.