Q. Which of the following are condensation polymers?

1. Nylon-6,6
2. Terylene (PET)
3. Polyethylene
4. Bakelite

Select the correct answer using the codes given below:
Answer: Only 1, 2 and 4
Notes: Nylon-6,6 (a polyamide), Terylene/PET (a polyester), and Bakelite (a phenol-formaldehyde resin) are formed by condensation polymerization. Polyethylene is an addition polymer, not a condensation polymer. Therefore, only 1, 2, and 4 are condensation polymers.