$ C(s)\,\, + \,\,{O_2}(g)\,\, \to \,\,C{O_2}\,(g)$ $\Delta H = \,\, - \,94\,\,kcal$
${H_2}\,(g)\,\, + \,\,\frac{1}{2}\,{O_2}\,(g)\,\, \to \,\,{H_2}O\,(g),$ $\Delta H\,\, = \,\, - \,68\,\,kcal$
${C_2}{H_5}OH\,(\ell )\,\, + \,\,3{O_2}\,(g)\,\, \to \,\,2C{O_2}\,(g)\,\, + \,\,3{H_2}O\,(\ell ),$$\Delta H\,\, = \,\,\, - \,327\,\,kcal$
\(2C\,\,(s)\,\, + \,\,3{H_2}\,(g)\,\, + \,\,\frac{1}{2}\,{O_2}\,(g)\,\, \to \,\,{C_2}{H_5}OH(\ell ),\,\,\Delta {H_f}\, = \,\,?\)
આપેલ માહિતી નીચે પ્રમાણે લખી શકાય કારણ કે ઉષ્મા રાસાયણિક સમીકરણએ બેઝિક સમીકરણ તરીકે કાર્ય કરે છે.
\((i)\,\,2C\,\,(s)\,\, + \,\,2{O_2}\,(g)\,\, \to \,\,2C{O_2}\,(g)\) \(\Delta H\,\, = \,\, - \,\,188\,\,kcal\)
\((ii)\,\,3{H_2}\,(g)\,\, + \,\,\frac{3}{2}\,\,{O_2}\,(g)\,\, \to \,\,3{H_2}O\,(\ell )\,;\) \(\Delta H\,\, = \,\, - \,\,204\,\,kcal\)
\((iii)\,\,2C{O_2}\,(g)\,\, + \,\,3{H_2}O\,(\ell )\,\, \to \,\,{C_2}{H_5}OH\,(\ell )\,\, + \,\,3{O_2}\,(g)\) \(\Delta H\,\, = \,\, + \,\,327\,\,kcal\)
ઉમેરવાથી \(2C\,(s)\, + \,\,3{H_2}\,(g)\,\, + \,\,\frac{1}{2}\,{O_2}\,(g)\,\, \to \,\,{C_2}{H_5}OH\,(\ell ),\,\,\Delta {H_f}\, = \,\, - \,65\,\,kcal/mol\)
$C _{2} H _{6} \rightarrow C _{2} H _{4}+ H _{2}$
પ્રકિયા એન્થાલ્પી $\Delta_{ r } H =...........{ kJ\, mol ^{-1}}$.
[આપેલ : બંધ એન્થાલ્પી $kJ$ $mol$ $^{-1}:C-C : 347, C = C : 611 ; C - H : 414, H - H : 436]$