The $$\Delta \mathrm{H}_{(\mathrm{f})}^{\mathrm{o}}$$ of $$\mathrm{NO}_2(\mathrm{~g})$$ and $$\mathrm{N}_2 \mathrm{O}_4(\mathrm{~g})$$ are 16.0 and $$4.0 \mathrm{k} \mathrm{cal} \mathrm{mol}^{-1}$$ respectively. The heat of dimerisation of $$\mathrm{NO}_2$$ in $$\mathrm{k}$$ cal is :

At Constant volume, the heat required to raise the temperature of $$4.48 \mathrm{~L}$$ of an ideal gas at STP by $$15^{\circ} \mathrm{C}$$ is 12.0 calories. The $$\mathrm{C_p}$$ of the gas is _____________ $$(\mathrm{R}=2 \mathrm{~Cal} \mathrm{~kg}^{-1} \mathrm{~mol}^{-1})$$

The correct option for free expansion of an ideal gas under adiabatic condition is:

The standard enthalpy of formation of $$\mathrm{CH}_4$$, the standard enthalpy of sublimation of Carbon and the bond dissociation enthalpy of Hydrogen gas are $$-74.8,+719.6$$ and $$436 \mathrm{~kJ} / \mathrm{mol}$$ respectively. What is the bond enthalpy of $$\mathrm{C}-\mathrm{H}$$ bond in Methane?