On the basis of the following equations,the heat of dimerisation of $NO_2$ will be:
$(i) \ N_2 + 2O_2 \to 2NO_2, \Delta H = 67.9 \ kJ$
$(ii) \ N_2 + 2O_2 \to N_2O_4, \Delta H = 9.3 \ kJ$

What is the value of $\Delta H^{\circ}$ for the formation of ethanol from ethene gas and liquid water from the following data (in $kJ$)?
$(i)$ $C_2H_5OH_{(l)} + 3O_{2_{(g)}} \longrightarrow 2CO_{2_{(g)}} + 3H_2O_{(l)}$ $\Delta H^{\circ} = -1368 \ kJ$
$(ii)$ $C_2H_{4_{(g)}} + 3O_{2_{(g)}} \longrightarrow 2CO_{2_{(g)}} + 2H_2O_{(l)}$ $\Delta H^{\circ} = -1410 \ kJ$

The heat of formation of methane $C_{(s)} + 2H_{2(g)} \to CH_{4(g)}$ at constant pressure is $-18500 \ cal$ at $25 \ ^oC$. The heat of reaction at constant volume would be (in $cal$)

The heats of combustion of carbon and carbon monoxide are $-393.5 \ kJ \ mol^{-1}$ and $-283.5 \ kJ \ mol^{-1},$ respectively. The heat of formation (in $kJ \ mol^{-1}$) of carbon monoxide per mole is:

The standard enthalpy of atomization of ethane according to the equation $C_2H_{6(g)} \rightarrow 2C_{(g)} + 6H_{(g)}$ is $622 \ kJ \ mol^{-1}$. If the standard mean $C-H$ bond dissociation enthalpy is $90 \ kJ \ mol^{-1}$,the standard mean dissociation enthalpy of the $C-C$ bond (in $kJ \ mol^{-1}$) is:

$C_6H_{6(l)} + 7.5O_{2(g)} \to 6CO_{2(g)} + 3H_2O_{(g)}$; $\Delta H = -3267.7 \ kJ \ mol^{-1}$. Given that the standard enthalpies of formation of $CO_{2(g)}$ and $H_2O_{(g)}$ are $-393.5 \ kJ \ mol^{-1}$ and $-285.85 \ kJ \ mol^{-1}$ respectively,calculate the standard enthalpy of formation of benzene $(C_6H_{6(l)})$.