Depolymerization of paraformaldehyde occurs with what condition?

• A. Heating the solution.
• B. Cooling the solution.
• C. Exposure to light.
• D. Addition of acid.

Answer: (A)

Depolymerization happens when paraformaldehyde is heated. It’s a polymer made of formaldehyde units linked together, so applying heat provides the energy that breaks those bonds and releases formaldehyde monomer, which then dissolves in water to form formalin. Cooling doesn’t promote this breakdown and tends to keep the solid polymer intact. Light exposure isn’t a reliable trigger for depolymerization, and adding acid isn’t the typical driver for breaking down paraformaldehyde in this context. So heating is the condition that converts the solid polymer back into formaldehyde-containing solution.