Mixing of non-reacting gases is generally accompanied by

During which of the following processes does entropy decrease?

Which of the following reactions has $\Delta S > 0$?

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?

Direct conversion of $A$ to $B$ is difficult,so it is carried out by the path shown below. If $e.u.$ is the entropy unit,what will be $\Delta S_{(A \rightarrow B)}$?
Given:
$\Delta S_{(A \rightarrow C)} = 50 \ e.u.$
$\Delta S_{(C \rightarrow D)} = 30 \ e.u.$
$\Delta S_{(B \rightarrow D)} = 20 \ e.u.$

The entropy values (in $J K^{-1} mol^{-1}$) of $H_{2(g)} = 130.6$,$Cl_{2(g)} = 223.0$ and $HCl_{(g)} = 186.7$ at $298 \ K$ and $1 \ atm$ pressure. Then entropy change for the reaction $H_{2(g)} + Cl_{2(g)} \to 2HCl_{(g)}$ is :-