Question

Identify ureaformaldehyde resin from following polymers?

• A.

  

• B.

  

• C. \([\text{NH}-\text{CO}-\text{NH}-\text{CH}_2]_n\)
• D. \([\text{NH}-(\text{CH}_2)_5-\text{CO}]_n\)

Hint:

Urea-formaldehyde resin repeats the unit NH-CO-NH-CH2.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Urea-formaldehyde resin is a condensation polymer formed from urea (\(\text{NH}_2\text{CONH}_2\)) and formaldehyde (HCHO). The repeating unit contains \(-\text{NH-CO-NH-CH}_2-\).

Step 2: Check the Options:
Option (A) shows \(-[\text{CH}_2-\text{CH}(\text{CONH}_2)]_n-\), which is polyacrylamide, an addition polymer of acrylamide.
Option (B) shows a chain with a phenyl group on every second carbon, which is polystyrene.
Option (C) is \([\text{NH-CO-NH-CH}_2]_n\), the urea-formaldehyde repeating unit.
Option (D) is \([\text{NH-(CH}_2)_5\text{-CO}]_n\), which is nylon-6.

Step 3: Conclusion:
Only option (C) matches the urea-formaldehyde resin.

Final Answer:
The repeat unit with urea and CH\(_2\) is option (C). \[ \boxed{\text{(C) } [\text{NH-CO-NH-CH}_2]_n} \]