Which of these undergo polymerisation?

• A

  $\mathrm{CH}_{3} \mathrm{OH}$
• B

  $\mathrm{C}_{2} \mathrm{H}_{5} \mathrm{OH}$
• Correct answer
  C

  $\mathrm{CH}_{3} \mathrm{CHO}$
• D

  none of these

Solution

Acetone on polymerisation give mesitylene
3 molecules of acetaldehyde produce paraldehyde $\left(\mathrm{CH}_{3} \mathrm{CHO}\right)_{3}$ and 4 molecules of it produce metaldehyde $\left(\mathrm{CH}_{3} \mathrm{CHO}\right)_{4}$.

Hence, the correct answer is option: 'C'.