The molar enthalpies of combustion of $C_2H_2(g), C (graphite)$ and $H_2(g)$ are $-1300, -394,$ and $-286\, KJ \,mol^{-1}$, respectively. The standard enthalpy of formation of $C_2H_2(g)$ is .......$kJ \,mol^{-1}$
→Which of the following $IUPAC$ name is correct for $\begin{array}{*{20}{c}}
{C{H_2} - CH - C{H_2}}\\
{|\,\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,\,\,\,\,\,\,\,|\,\,\,\,\,\,}\\
{\,\,CHO\,\,\,CHO\,\,CHO}
\end{array}$ ?
→In the reaction product $D$ is $\begin{array}{*{20}{c}}
{C{H_2}} \\
{||\,\,\,\,\,\,\,\,} \\
{C{H_2}}
\end{array}$ $\xrightarrow{{B{r_2}/CC{l_4}}}A\xrightarrow{{KCN}}B\xrightarrow{{{H_3}{O^ + }}}C\xrightarrow{\Delta }D$
→