For which one of the following reactions, the entropy change is positive?

Calculate the entropy change for the melting of $1 \, kg$ of ice at $0 \, ^\circ C$ in $SI$ units. (Latent heat of fusion of ice = $80 \, cal \, g^{-1}$) (in $.67$)

When the same quantity of heat is absorbed by a system at two different temperatures $T_{1}$ and $T_{2}$,such that $T_{1} > T_{2}$,the changes in entropy are $\Delta S_{1}$ and $\Delta S_{2}$ respectively. Then:

Given the standard entropy values at $298 \ K$ and $1 \ atm$ as $H_2(g) : 130.6 \ J \ K^{-1} \ mol^{-1}$,$Cl_2(g) : 223.0 \ J \ K^{-1} \ mol^{-1}$,and $HCl(g) : 186.7 \ J \ K^{-1} \ mol^{-1}$,calculate the entropy change $(\Delta S^{\circ})$ in $J \ K^{-1} \ mol^{-1}$ for the reaction: $H_2(g) + Cl_2(g) \rightarrow 2HCl(g)$

Which state functions are required to understand the second law of thermodynamics?

One mole of $NaCl$ $(s)$ on melting absorbed $30.5 \ kJ$ of heat and its entropy increased by $28.8 \ J \ K^{-1}$. The melting point of $NaCl$ is ............. $K$.