$(i)\,\,\Delta H_f^o\,\,of\,{H_2}{O_{(\ell )}}\, = \,\, - 68.3\,K\,\,cal\,\,mo{l^{ - 1}}$
$(ii)\,\,\Delta H_{comb}^o\,\,of\,{C_2}{H_2}\, = \,\, - 337.2\,K\,\,cal\,\,mo{l^{ - 1}}$
$(iii)\,\,\Delta H_{comb}^o\,\,of\,\,{C_2}{H_4}\,\, = \,\, - \,363.7\,\,K\,\,cal\,\,mo{l^{ - 1}} $
${C_2}{H_2} + {H_2} \to {C_2}{H_4},\,\,\Delta H = ??$
$\Delta H = {(\Delta {H_{comb.}})_{{\text{Reactant}}}} - {(\Delta {H_{comb}})_{\ Product}}$
$\Delta H = - 337.2 - 68.3 - (363.7) = - 41.8\,K\,cal$
${C_4}{H_{10}}_{(g)}\,\, + \,\,\frac{{13}}{2}\,{O_2}_{(g)}\,\, \to \,\,4C{O_2}_{(g)}\,\, + \,\,5{H_2}O(\ell )\,\,\,\,\,\,\,;$
$\,\,\,\,\,\,\Delta H\,\, = \,\, - 2658\,\,KJ$
જો પરિવારને દરરોજ રાંધવા માટે $15000\,KJ$ ઊર્જા જરૂર પડે. તો સીલીન્ડર ......દિવસ સુધી ચાલશે ?