The heat of neutralization of four acids $A$,$B$,$C$,and $D$ are $-13.0$,$-12.6$,$-9.2$,and $-11.7 \ KCal/eq$ respectively when neutralized by $NaOH$. The order of acidic strength of the four acids will be:

Given: $2Fe + \frac{3}{2} O_2 \to Fe_2O_3$,$\Delta H = -193.4 \ kJ$;
$Mg + \frac{1}{2} O_2 \to MgO$,$\Delta H = -140.2 \ kJ$.
What is the $\Delta H$ of the reaction $3Mg + Fe_2O_3 \to 3MgO + 2Fe$ in $kJ$?

Consider the following data :
Heat of formation of $CO_{2(g)} = -393.5 \ kJ \ mol^{-1}$
Heat of formation of $H_2O_{(l)} = -286.0 \ kJ \ mol^{-1}$
Heat of combustion of benzene $= -3267.0 \ kJ \ mol^{-1}$
The heat of formation of benzene is $........... \ kJ \ mol^{-1}$. $(Nearest \ integer)$

Given $C + O_2 \rightarrow CO_2 + 94.2 \ kcal$,$\Delta H = -94.2 \ kcal$; $H_2 + 1/2 O_2 \rightarrow H_2O + 68.3 \ kcal$,$\Delta H = -68.3 \ kcal$ and $CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + 210.8 \ kcal$,$\Delta H = -210.8 \ kcal$. Calculate the heat of formation of methane $(CH_4)$ in $kcal$.

From the following thermochemical equations,find out the heat of ionisation $Z$ for a weak acid $HA$:
$HA \to A^{-} + H^{+} , \Delta H = Z$
$H^{+} + OH^{-} \to H_2O , \Delta H = X$
$HA + OH^{-} \to A^{-} + H_2O , \Delta H = Y$

Which of the following equations is used to calculate the standard enthalpy change of a reaction $(\Delta_r H^\circ)$?