In the second step of this reaction, isocyanic acid reacts to form melamine and carbon dioxide: hnco(l)→c3n3(nh2)3(l)+co2(g) balance this reaction and enter the coefficients below. enter the coefficients in order separated by commas (e. g., 1,4,5, where 1 indicates the lack of a coefficient).

Formula of isocyanic acid is HNCO. It colourless, volatile compound. It is poisonous inorganic compound. Melamine is synthesized from urea. The reaction involves two steps. In first step, urea gets converted to isocyanic acid  which is an intermediate. In the second step, isocyanic acid gives melamine (molecular formula C₃H₆N₆) and carbon dioxide (CO₂). The balanced chemical reaction involved in second step is given below:

6 HNCO → 1 C₃N₃(NH₂)₃ + 3CO₂

The co-efficient of the reaction are: 6, 1, 3