Melamine polymer is formed by the condensation of

Formation of Melamine-Formaldehyde Polymer

The reaction depicts the synthesis of a widely used thermosetting plastic, commonly known as melamine resin. This process occurs in two distinct stages: a condensation reaction followed by polymerization.

Step 1: Formation of the Resin Intermediate

• Reactants: The process begins with Melamine (a heterocyclic aromatic compound containing three primary amine groups) and Formaldehyde ($HCHO$).
• Reaction: An initial addition reaction takes place where one of the amino groups ($-NH_2$) of melamine reacts with the carbonyl carbon of formaldehyde.
• Product: This forms a methylol derivative known as the Resin intermediate. Structurally, one of the $-NH_2$ groups has been converted into an $-NHCH_2OH$ group.

Step 2: Polymerisation

• Process: The intermediate molecules undergo condensation polymerization.
• Mechanism: Under appropriate conditions (usually heating), the hydroxyl group ($-OH$) from the methylol unit of one intermediate molecule reacts with an active hydrogen from an unreacted amino group ($-NH_2$) of an adjacent molecule. This results in the elimination of a water molecule ($H_2O$).
• Linkage: This condensation forms a strong methylene bridge ($-CH_2-$) between the triazine rings, creating a robust polymer chain.
• Final Product: Because melamine possesses three reactive amine sites, it can form linkages in multiple directions. This leads to the Melamine polymer, a highly cross-linked, three-dimensional network. This heavy cross-linking gives the final material its characteristic hardness, heat resistance, and durability (commonly used in unbreakable plastic crockery).
  
  Thus, the correct option is B.