Question

Terylene is a condensation polymer of ethylene glycol and:
(A) Benzoic acid
(B) Phthalic acid
(C) Terephthalic acid
(D) Salicylic acid

Answer 1

Hint: We should know that Terylene is the most common type of polyester. It is synthesized by esterification of diol and a di-carboxylic acid.
\[nHOOC-{{C}_{6}}{{H}_{4}}-COOH\,+\,nHOC{{H}_{2}}-C{{H}_{2}}OH\,\xrightarrow{-{{H}_{2}}O}{{\left[ -CO-{{C}_{6}}{{H}_{4}}-CO-OC{{H}_{2}}-C{{H}_{2}}- \right]}_{n}}\]

Complete step by step answer:
We should know that Terylene is a synthetic polyester fibre. It is also known as Dacron. It is extensively used in the textile industry to produce readymade garments. This synthetic polyester fibre was first produced in 1941 by polymerizing ethylene glycol with Terephthalic acid at a suitable temperature. The catalyst used is a mixture of zinc acetate and antimony trioxide. Production of Terylene involves Polycondensation. Polycondensation is a chemical condensation reaction in which the formation of a compound with high molecular weight is the result.
In condensation polymerization, when the monomers are joined together a small molecule gets eliminated. That's different from addition polymerization which produces polymers like poly (ethene) - in that case, nothing is lost when the monomers join together.
Polyester is made by a reaction involving an acid with two -COOH groups, and an alcohol with two -OH groups.
It is characterized by the lightness and crease resistance and used for clothing, sheets, ropes and sails. Sometimes it is mixed with natural fibers like wool and cotton.

Hence, the correct answer is Option (C) Terephthalic acid.

Note: Terylene is the strongest polymer known to us. It must not be confused with polyester which represents all polymers produced in a similar fashion.