Which of the following compounds has the highest standard molar entropy?

One mole of an ideal gas expands adiabatically and reversibly from its initial pressure to half of its initial pressure. What will be the value of $\Delta S$ in $J \ K^{-1} \ mol^{-1}$? $[\ln 2 = 0.693$ and $R = 8.314 \ J \ mol^{-1} \ K^{-1}]$

State the limitation of the $2^{nd}$ law of thermodynamics.

Calculate the entropy change of the surrounding if $2 \ moles$ of $H_2$ and $1 \ mole$ of $O_2$ gas combine to form $2 \ moles$ of liquid water by releasing $525 \ kJ$ of heat to the surrounding at constant pressure and at $300 \ K$. (in $J \ K^{-1}$)

Calculate the entropy change when $1 \, \text{mole}$ of ice is converted into water at $0 \, ^\circ\text{C}$. (The enthalpy change for the conversion of ice to liquid at $0 \, ^\circ\text{C}$ is $6.0 \, \text{kJ} \, \text{mol}^{-1}$).

For which of the following processes is $\Delta S$ negative?