Which of the following statements about ethylene and polyethylene is true?
a) the polymer has the same properties as the monomer.
b) the polymer has alternating double and single bonds between carbons, while the monomer has only single bonds between carbons.
c) the polymer has alternating double and single bonds between carbons, while the monomer has only double bonds between carbons.
d) the polymer has only single bonds between carbons, while the monomer has only double bonds between carbons.

D is the correct option.

Explanation:

The carbon atoms are bonded together by a double bond.

The carbon atoms are bonded together by single bonds.

Lets analyse each option:

A) Its false. Lets look at the obvious: Ethylene is a gas and polyethylene is a solid. Monomers and polymers have very different properties.

B) Its false. Polyethylene doesnt have double bonds.

C) False as well. Polyethylene doesnt have double bonds.

D) True. It is evident from the structure of the the monomer and polymer that I've shown above. I'll also provide neat structures in the attachments.