For which of the following processes will the value of $\Delta H^{\circ} - \Delta G^{\circ}$ be approximately zero?

The values of $\Delta H$ for the combustion of ethene and ethyne are $-341.1 \ kcal$ and $-310.0 \ kcal$ respectively. Which of the following is a better fuel?

Calculate the difference between heat of combustion of carbon monoxide gas at constant pressure and at constant volume at $27^{\circ} C$ (in $cal$)? $(R = 2 \ cal \ K^{-1} \ mol^{-1})$

For the complete combustion of methanol
$CH_3OH_{(l)} + \frac{3}{2} O_{2(g)} \rightarrow CO_{2(g)} + 2H_2O_{(l)}$
the amount of heat produced as measured by a bomb calorimeter is $726 \ kJ \ mol^{-1}$ at $27^{\circ}C$. The enthalpy of combustion for the reaction is $-x \ kJ \ mol^{-1}$,where $x$ is $.....$ (Nearest integer).
(Given: $R = 8.3 \ J \ K^{-1} \ mol^{-1}$)

$A$ gas at $10 \, atm$ pressure and $300 \, K$ temperature undergoes adiabatic reversible expansion to $5 \, atm$ pressure and $290 \, K$ temperature. The molar heat capacity $C_v$ of the gas in $cal \, mol^{-1} \, K^{-1}$ is:

Assertion $(A)$: If heat of combustion of $C_2H_6$ is $X \ kJ \ mol^{-1}$,heat liberated on combustion of $150 \ g$ of $C_2H_6$ is $5X \ kJ$.
Reason $(R)$: Enthalpy is an extensive property.