The enthalpy of neutralisation of $KOH$ by a weak acid $(HA)$ is $-12.2 \ kcal \ mol^{-1}$. If the weak acid is $10 \%$ ionised,then the enthalpy of dissociation of $1 \ mole$ of $HA$ is. Given that the enthalpy of neutralisation of $KOH$ by $HCl$ is $-13.7 \ kcal \ mol^{-1}$.

If for a given substance the melting point is $T_B$ and the freezing point is $T_A$,then which graph correctly shows the variation of entropy change $(\Delta S)$ with temperature $(T)$?

Calculate the work done during the combustion of $0.138 \ kg$ of ethanol,$(C_2H_5OH_{(l)})$ at $300 \ K$. Given: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$ and molar mass of ethanol $= 46 \ g \ mol^{-1}$. (in $J$)

Heat of combustion of $CH_4, C_2H_4$ and $C_2H_6$ are $-890, -1411$ and $-1560 \ kJ/mol$ respectively. Which has the lowest calorific value?

The molar heat of formation of $NH_4NO_{3(s)}$ is $-367.54 \ kJ \ mol^{-1}$ and those of $N_2O_{(g)}$ and $H_2O_{(l)}$ are $+81.46 \ kJ \ mol^{-1}$ and $-285.78 \ kJ \ mol^{-1}$ respectively at $25 \ ^oC$ and $1.0 \ atm$ pressure. Calculate $\Delta U$ at $25 \ ^oC$ for the reaction:
$NH_4NO_{3(s)} \rightarrow N_2O_{(g)} + 2H_2O_{(l)}$ (in $kJ$)

Identify the incorrect statements among the following:
$(a)$ All enthalpies of fusion are positive.
$(b)$ The magnitude of enthalpy change does not depend on the strength of the intermolecular interactions in the substance undergoing phase transformations.
$(c)$ When a chemical reaction is reversed,the value of $\Delta_r H^{\circ}$ is reversed in sign.
$(d)$ The change in enthalpy is dependent on the path between the initial state (reactants) and final state (products).
$(e)$ For most of the ionic compounds,$\Delta_{\text{sol}} H^{\circ}$ is negative.