Maximum entropy will be in which of the following?

Which of the following processes takes place with a decrease of entropy?

Melting point of a solid is $x \ K$ and its latent heat of fusion is $600 \ cal \ mol^{-1}$. The entropy change for fusion of $1 \ mol$ solid is $2 \ cal \ mol^{-1} \ K^{-1}$. The value of $x$ will be......$K$

If the enthalpy change for the following reaction at $300 \ K$ is $+7 \ kJ \ mol^{-1}$,find the entropy change of the surrounding (in $J \ K^{-1}$)?
$H_2O_{(s)} \longrightarrow H_2O_{(l)}$

What is entropy?

For a reversible expansion of $5 \, \text{mol}$ of an ideal gas at $27 \, ^\circ\text{C}$ from a volume of $8 \, \text{dm}^3$ to $80 \, \text{dm}^3$,the change in entropy is ...... $J \, K^{-1}$.