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 ............. $K$.

For the reactions,
$2 Cl_{(g)} \longrightarrow Cl_{2(g)}$
$CO_{2(g)} \longrightarrow CO_{(g)} + \frac{1}{2} O_{2(g)}$
What are the signs of $\Delta S$, respectively?

The molar entropy is maximum for

Find the change in entropy for the fusion of $1 \, mol$ of ice in $J \, K^{-1} \, mol^{-1}$. The melting point of water is $273 \, K$ and the molar enthalpy of fusion for water is $6.0 \, kJ \, mol^{-1}$.

Calculate the entropy change in $J \, mol^{-1} K^{-1}$ for the isothermal reversible expansion of $2 \, mol$ of an ideal gas from a volume of $10 \, dm^3$ to $100 \, dm^3$ at $27 \, ^oC$.

$A$ 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 $J$?