STD 11 - 8.2 Organic chemistry isomerism — JEE STD 11 Science — Question

$\left. \begin{gathered}
  {\text{4N}}{{\text{H}}_{3(g)}}{\text{ + 5}}{{\text{O}}_{2(g)}} \to {\text{ 4N}}{{\text{O}}_{(g)}}{\text{ +  6}}{{\text{H}}_{\text{2}}}{{\text{O}}_{{\text{(l)}}}} \hfill \\
  {\text{2N}}{{\text{O}}_{(g)}}{\text{ + }}{{\text{O}}_{2(g)}} \to {\text{2N}}{{\text{O}}_{2(g)}} \hfill \\
  {\text{3N}}{{\text{O}}_{2(g)}}{\text{ +  }}{{\text{H}}_{{\text{ 2}}}}{{\text{O}}_{(l)}} \to {\text{2H N}}{{\text{O}}_{3(aq)}}{\text{ +  N}}{{\text{O}}_{(g)}} \hfill \\ 
\end{gathered}  \right|\begin{array}{*{20}{c}}
  {\Delta H(kJ)} \\ 
  { - 904} \\ 
  { - 112} \\ 
  { - 140} 
\end{array}$

$3 HC \equiv CH _{( g )} \rightleftharpoons C _{6} H _{6(\ell)}$

[Given: $\Delta_{f} G ^{\circ}( HC \equiv CH )=-2.04 \times 10^{5}\, J mol ^{-1}$

$\Delta_{f} G ^{\circ}\left( C _{6} H _{6}\right)=-1.24 \times 10^{5}\, J mol ^{-1} ; R =8.314\,\left. J K ^{-1} mol ^{-1}\right]$

[Given : Atomic masses : $C : 12.0 u$,$H : 1.0 u , O : 16.0 u ]$