Q.Write the reaction of thermal decomposition of sodium azide.

Dinitrogen, $N_2$, has two nitrogen atoms joined by an extremely strong triple bond ($N \equiv N$, bond enthalpy about 941 kJ/mol) with a short bond length, making it kinetically inert at room temperature even though it is thermodynamically reactive — the activation energy needed to break the triple bond is very high, so $N_2$ reacts only at high temperature, with catalysts, or with very reactive species. In the laboratory it is prepared by gently heating an aqueous ammonium chloride solution with sodium nitrite, $NH_4Cl + NaNO_2 \rightarrow N_2 + NaCl + 2H_2O$, or by thermal decomposition of sodium or barium azide, e.g. $2NaN_3 \rightarrow 2Na + 3N_2$. Industrially it is obtained by fractional distillation of liquefied air. $N_2$ makes up about 78% …