Which of the following reactions will have the value of $\Delta S$ with a negative sign?

$30.4 \, kJ$ of heat is required to melt one mole of sodium chloride and the entropy change at the melting point is $28.4 \, J \, K^{-1} \, mol^{-1}$ at $1 \, atm$. The melting point of sodium chloride is $........... \, K$ (Nearest Integer).

If the enthalpy of vaporization for water is $186.5 \ kJ \ mol^{-1}$,the entropy of its vaporization will be ...... $J \ K^{-1} \ mol^{-1}$ (Assume the boiling point of water is $373 \ K$).

Will ice at $273 \ K$ placed in a surrounding at $298 \ K$ melt to form water at $273 \ K$? Prove this statement. The molar enthalpy of fusion of ice is $6.025 \ kJ \ mol^{-1}$.

Identify from the following physical transformations that exhibits a decrease in entropy.

$A$ heat engine is operating between $500 \ K$ and $300 \ K$. If the engine absorbs $100 \ J$ of heat,which of the following is an impossible amount of heat rejected by the engine in $J$?