One mole of which of the following has the highest entropy?

The total entropy change for a system and its surroundings increases,if the process is

Standard entropies of $X_2, Y_2$ and $XY_5$ are $70, 50$ and $110 \ J \ K^{-1} \ mol^{-1}$ respectively. The temperature in Kelvin at which the reaction $\frac{1}{2} X_2 + \frac{5}{2} Y_2 \rightarrow XY_5$ with $\Delta H = -35 \ kJ \ mol^{-1}$ will be at equilibrium is . . . . . . (Nearest integer).

Predict in which of the following,entropy increases or decreases:
$(i)$ $A$ liquid crystallizes into a solid.
$(ii)$ Temperature of a crystalline solid is raised from $0 \, K$ to $115 \, K$.
$(iii)$ $2NaHCO_{3(s)} \to Na_2CO_{3(s)} + CO_{2(g)} + H_2O_{(g)}$
$(iv)$ $H_{2(g)} \to 2H_{(g)}$

For a reversible adiabatic expansion of an ideal gas,which of the following is equal to zero?

Change in entropy is positive for