Question

# Dacron is a polymer of:A. Ethylene glycol and formaldehydeB. Ethylene glycol and phenolC. Ethylene glycol and phthalic acidD. Ethylene glycol and terephthalic acid

Hint: Think about the common name of dacron; terylene. It is used regularly in the production of various fabrics. The name will give you an idea about the unit molecules involved in the monomeric unit.

We know that the common name of dacron is terylene. The name is derived from one of the molecules involved in the making of its monomer. Ethylene glycol and terephthalic acid undergo condensation for the monomer of dacron. Following is the reaction that terephthalic acid and ethylene glycol undergo to form the monomer unit of dacron:

Here, we can see that one ${{H}_{2}}O$ molecule is lost to form the unit. Thus, it is called a condensation reaction.
So, the correct answer is “Option D”.

Additional Information: Dacron is a polymer that has a fairly widespread use in fabrics. It has high tensile strength and is fairly resistant to stretching whether the fabric is wet or dry. It has a high resistance to being degraded by chemical bleaches and abrasive materials. Various fabrics in which it is used include curtains, firefighter hoses, formal shirts and mixing with other woolen wear.

Note:Please do not get confused between phthalic acid and terephthalic acid. They have the same molecular formula but are structural isomers of each other. Both have two acid groups attached to a benzene ring. The difference is that while terephthalic acid is a para-isomer, phthalic acid is the ortho-isomer of the same compound.