In a reversible process,under what condition does the heat exchanged become a state function?

Calculate the work done for the following reaction at $27^{\circ}C$: $C_2H_4(g) + H_2(g) \rightarrow C_2H_6(g)$ $(R = 8.314 \text{ J K}^{-1} \text{mol}^{-1})$ (in $\text{ J}$)

Calculate the difference between $\Delta H$ and $\Delta U$ for the following reaction at $25^{\circ} C$:
$C_2H_{6(g)} + 3.5O_{2(g)} \rightarrow 2CO_{2(g)} + 3H_2O_{(l)}$
(Given: $R = 8.314 \ J \ K^{-1} \ mol^{-1}$) (in $kJ$)

Identify the incorrect statements from the following.
$I$. For adiabatic process,$\Delta U = w_{ad}$
$II$. Enthalpy is an intensive property
$III$. For the process,$H_2O_{(l)} \rightarrow H_2O_{(s)}$,the entropy increases

The energy of combustion per mole of $H_2$,$LPG$,and octane follows the order:

For the reaction at $300 \, K$,$A_{(g)} + B_{(g)} \to C_{(g)}$,given $\Delta U = -3 \, kcal$ and $\Delta S = -10 \, cal/K$. The value of $\Delta G$ will be $...... \, cal$.