Bond dissociation enthalpy of $H_2, Cl_2$ and $HCl$ are $434, 242$ and $431 \ kJ \ mol^{-1}$ respectively. Enthalpy of formation of $HCl$ is ............... $kJ \ mol^{-1}$

If heat of neutralization is $-13.7 \, KCal$ at $25 \, ^oC$ and $\Delta H_f^o (H_2O) = -68 \, KCal$,then the standard enthalpy of formation of $OH^{-}$ will be.....$KCal$. (in $.3$)

Heats of combustion $(\Delta H^o)$ for $C_{(s)}$,$H_{2(g)}$ and $CH_{4(g)}$ are $-94$,$-68$ and $-213 \ kcal/mol$ respectively. The value of $\Delta H^o$ for the reaction,$C_{(s)} + 2H_{2(g)} \to CH_{4(g)}$ is $..... \ kcal$.

The $\Delta H_f^o$ for $CO_{2(g)}$,$CO_{(g)}$ and $H_2O_{(g)}$ are $-393.5$,$-110.5$ and $-241.8 \ kJ \ mol^{-1}$ respectively. The standard enthalpy change (in $kJ$) for the reaction $CO_{2(g)} + H_{2(g)} \to CO_{(g)} + H_2O_{(g)}$ is

Observe the following reaction:
$2 A_{2(g)} + B_{2(g)} \xrightarrow{T(K)} 2 A_2 B_{(g)} + 600 \ kJ$
The standard enthalpy of formation $(\Delta_f H^{\circ})$ of $A_2 B_{(g)}$ is:

The heat of neutralisation of $NH_4OH$ and $HCl$ is: