ce chem mc

I have just read the HKCEE syllabus in the website of HKEAA. In the syllabus, only two condensation polymers are included, and they are nylon and polyester (as in (2)). However, this question involves two other condensation polymers, urea-methanal and protein (a natural polymer).
Both (1), (2) and (3) are correct.


圖片參考：http://ndc.hkcampus.net/~ndc-007/polymer1.jpg


圖片參考：http://ndc.hkcampus.net/~ndc-007/polymer2.jpg


圖片參考：http://ndc.hkcampus.net/~ndc-007/polymer3.jpg

呢題係07年既CHEM,
我諗(1)同(2)你應該知點解係既,
我想見到每個monomer都有2個functional group,
condensation polymerization講明左一定要由2個molecules有2個唔同既functional 先可以carry out,
咁(1)果個,左手邊果個可以甩個H同黎,而右邊果個可以甩H2N出黎,變成NH3,

(2),左手甩個H,右邊甩OH,加埋係H2O
到(3)都係,都係會放出H2O

the answer is C
2 and 3 can form polymers and a side product.
so it is a condensation polymer.
2 can form a ester polymer and a water molecule
3 can form an amide polymer and a ammonia molecule