Question
Given, ${C_{(graphite)}} + {O_2} \to C{O_2}(g)$;
${\Delta _r}{H^o}$ = - 393.5 kJ mol-1
${{\rm H}_2}(g)$ + ${1 \over 2}{O_2}(g)$$\to {{\rm H}_2}{\rm O}(l)$
${\Delta _r}{H^o}$ = - 285.8 kJ mol-1
$C{O_2}(g)$ + $2{{\rm H}_2}{\rm O}(l) \to$ $C{H_4}(g)$ + $2{O_2}(g)$
${\Delta _r}{H^o}$ = + 890.3 kJ mol-1
Based on the above thermochemical equations, the value of ${\Delta _r}{H^o}$ at 298 K for the reaction
${C_{(graphite)}}$ + $2{{\rm H}_2}(g) \to$ $C{H_4}(g)$ will be :
${\Delta _r}{H^o}$ = - 393.5 kJ mol-1
${{\rm H}_2}(g)$ + ${1 \over 2}{O_2}(g)$$\to {{\rm H}_2}{\rm O}(l)$
${\Delta _r}{H^o}$ = - 285.8 kJ mol-1
$C{O_2}(g)$ + $2{{\rm H}_2}{\rm O}(l) \to$ $C{H_4}(g)$ + $2{O_2}(g)$
${\Delta _r}{H^o}$ = + 890.3 kJ mol-1
Based on the above thermochemical equations, the value of ${\Delta _r}{H^o}$ at 298 K for the reaction
${C_{(graphite)}}$ + $2{{\rm H}_2}(g) \to$ $C{H_4}(g)$ will be :