$\Delta H_f^o\left( {CO} \right) = - 110.5\,kJ\,mo{l^{ - 1}};$
$\Delta H_f^o\left( {C{O_2}} \right) = - 393.5\,kJ\,mo{l^{ - 1}}$
$\Delta H ^{\circ}=\left|\frac{1}{2} \Delta_1 H _{ N _2}^{\circ}+2 \Delta_1 H _{ CO _2}^{\circ}\right|-\left|\Delta_1 H _{ NO }^{\circ}+\Delta_1 H _{ CO }^{\circ}\right|$
$-372.2=\left|\frac{1}{2}(0)+(-393.5)\right|-\left|\Delta_1 H _{ NO }^0+(-110.5)\right|$
$\therefore \Delta_1 H _{ NO }^{\circ}=-393.5+110.5+372.2=-393.5+482.7$
$=89.2\, kJ\, mol ^{-1}$
${C_3}{H_8}(g) + 5{O_2}(g) \to \,\,3C{O_2}(g) + 4{H_2}O(l)$
(આપેલ : બોમ્બ કેલોરિમીટરની ઉષ્માક્ષમતા $20.0\, kJ/K.$ ધારી લો કે કોલસો એ શુધ્ધ કાર્બન છે.)
[આપેલ : $R =8.314 \,J mol ^{-1} K ^{-1}$ ધારી લો કે હાઈડ્રોજન એ એક આદર્શ વાયુ છે.] [ પરમાણ્વીય દળ $Fe = 55.85\, u$ છે.]
$(i)\,\,\Delta H_f^o\,\,of\,{H_2}{O_{(\ell )}}\, = \,\, - 68.3\,K\,\,cal\,\,mo{l^{ - 1}}$
$(ii)\,\,\Delta H_{comb}^o\,\,of\,{C_2}{H_2}\, = \,\, - 337.2\,K\,\,cal\,\,mo{l^{ - 1}}$
$(iii)\,\,\Delta H_{comb}^o\,\,of\,\,{C_2}{H_4}\,\, = \,\, - \,363.7\,\,K\,\,cal\,\,mo{l^{ - 1}} $