For a spontaneous process, the correct statement$(s)$ is (are):

The heats of combustion of $CH_4, C_2H_6, C_2H_4$,and $C_2H_2$ at the same temperature are $-212.8, -373.0, -337.0$,and $-310.5 \, Kcal$ respectively. Which of these gases is the best fuel?

Find the enthalpy of neutralisation in $kJ/mol$ for the reaction between $NH_4OH$ and $HCN$ in aqueous solution,given that the enthalpies of ionisation of $NH_4OH$ and $HCN$ are $7 \ kJ/mol$ and $8 \ kJ/mol$ respectively,and the enthalpy of neutralisation of a strong acid and a strong base is $-57.3 \ kJ/mol$.

At $298 \ K$,$\Delta_r U^{\ominus}$ and $\Delta_r S^{\ominus}$ for the following reaction are $-10.5 \ kJ$ and $+44.1 \ J \ K^{-1} \ mol^{-1}$ respectively. The reaction is: $2 \ X_{(g)} + Y_{(g)} \longrightarrow 2 \ Z_{(g)}$. What is $\Delta_r G^{\ominus}$ (in $kJ$) for this reaction? $(R = 8.314 \ J \ K^{-1} \ mol^{-1})$

Considering the reaction $C_{(s)} + O_{2(g)} \longrightarrow CO_{2(g)} + 393.5 \ kJ$,the signs of $\Delta H, \Delta S$,and $\Delta G$ respectively are:

Calculate $\Delta H^{\circ}$ for the reaction, $Na_2O_{(s)} + SO_{3(g)} \longrightarrow Na_2SO_{4(s)}$, given the following reactions:
$(A) \ Na_{(s)} + H_2O_{(l)} \longrightarrow NaOH_{(s)} + \frac{1}{2}H_{2(g)} \quad \Delta H^{\circ} = -146 \ kJ$
$(B) \ Na_2SO_{4(s)} + H_2O_{(l)} \longrightarrow 2NaOH_{(s)} + SO_{3(g)} \quad \Delta H^{\circ} = +418 \ kJ$
$(C) \ 2Na_2O_{(s)} + 2H_{2(g)} \longrightarrow 4Na_{(s)} + 2H_2O_{(l)} \quad \Delta H^{\circ} = +259 \ kJ$