Melamine polymer is formed by the condensation of:

Solution

Chemistry ma’am · 4 steps

Melamine is a triazine: three ring nitrogens alternating with three carbons, each carbon carrying NH₂.

1. Know the monomers. Melamine-formaldehyde resin forms when melamine condenses with formaldehyde, HCHO. All four options use HCHO, so the choice comes down to the amine.
2. What melamine is. Melamine is 2,4,6-triamino-1,3,5-triazine, C₃H₆N₆. Its six-membered ring has three N atoms alternating with three C atoms, and each ring carbon carries one -NH₂ group.

   Option	Ring	N atoms in ring	NH₂ groups
   (a)	1,3,5-triazine	3	3
   (b)	pyrimidine	2	3
   (c)	benzene	0	3
   (d)	pyridine	1	2

3. Condensation. The -NH₂ groups react with HCHO and lose water, building -NH-CH₂-NH⁻ links. Three amino groups per ring let the chains cross-link into a hard thermosetting network.
4. So. Only (a) has the triazine ring with three amino groups, so melamine polymer comes from (a) with HCHO.

The idea to keep. Melamine resin = melamine + HCHO. Melamine is a six-membered ring of alternating C and N (three of each), with an NH₂ on every carbon. Count the ring nitrogens before you pick.

Answer from the NTA final answer key. Solution by PrepWiser.