Biomolecules and Chemistry in Everyday Life 2 Question 4
5. Which of the following compounds is a constituent of the polymer $\left[\mathrm{HN}-\mathrm{O}-\mathrm{NH}-\mathrm{CH}{2} \rrbracket{n}\right.$ ?
(2019 Main, 9 April II)
(a) $\mathrm{N}$-methyl urea
(b) Methylamine
(c) Ammonia
(d) Formaldehyde
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Answer:
Correct Answer: 5. (d)
Solution:
- Monomer of $-\left[\mathrm{NH}-\stackrel{\mathrm{O}}{\mathrm{C}}-\mathrm{NH}-\mathrm{CH}{2}\right]{n}$ is formaldehyde. The polymer is also known as urea-formaldehyde resin. It is made from urea $\left(\mathrm{NH}{2} \mathrm{CONH}{2}\right)$ and formaldehyde $(\mathrm{HCHO})$.
$$ \begin{aligned} & \underset{\text { Urea }}{\mathrm{NH}{2} \mathrm{CONH}{2}}+\underset{\text { Formaldehyde }}{\mathrm{HCHO}} \xrightarrow{\text { Polymerisation }} \ &\left.\underset{\text { Urea-formaldehyde resin }}{\mathrm{O}}){n}^{\mathrm{OH}}-\mathrm{C}-\mathrm{NH}-\mathrm{CH}{2}\right)_{n} \end{aligned} $$
It is used for making unbreakable cups and laminated sheets.
