$\Delta H_f^o\left( {CO} \right) = - 110.5\,kJ\,mo{l^{ - 1}};$
$\Delta H_f^o\left( {C{O_2}} \right) = - 393.5\,kJ\,mo{l^{ - 1}}$
\(\Delta H ^{\circ}=\left|\frac{1}{2} \Delta_1 H _{ N _2}^{\circ}+2 \Delta_1 H _{ CO _2}^{\circ}\right|-\left|\Delta_1 H _{ NO }^{\circ}+\Delta_1 H _{ CO }^{\circ}\right|\)
\(-372.2=\left|\frac{1}{2}(0)+(-393.5)\right|-\left|\Delta_1 H _{ NO }^0+(-110.5)\right|\)
\(\therefore \Delta_1 H _{ NO }^{\circ}=-393.5+110.5+372.2=-393.5+482.7\)
\(=89.2\, kJ\, mol ^{-1}\)
(Given ${\Delta _{fus}}H = 6\, kJ\, mol^{-1}$ at $0\,^oC$,
$C_p(H_2O, l) =75.3\, J\, mol^{-1} \, K^{-1}$ ,
$C_p(H_2O, s) = 36.8\, J\, mol^{-1} \, K^{ -1}$ )