State the criteria for a spontaneous process in terms of $\Delta G$ at constant pressure and temperature.

For the given reaction: $H_{2(g)} + S_{(s)} \to H_2S_{(g)}$; $\Delta H_r = 100\, kJ/mol$ and $\Delta S_r = 400\, J/mol\cdot K$. The temperature at which the above reaction occurs reversibly is (Assuming $\Delta H_r$ and $\Delta S_r$ are independent of temperature) ..... $K$.

Consider the following reaction:
$A_{(g)} + 3 B_{(g)} \longrightarrow 2 C_{(g)} ; \Delta H^{\ominus} = -24 \ kJ$.
At $25^{\circ} C$,if $\Delta G^{\ominus}$ of the reaction is $-9 \ kJ$,the standard entropy change (in $J \ K^{-1}$) of the same reaction at the same temperature is:

Identify from the following the correct set of thermodynamic conditions for the reaction to be spontaneous below equilibrium temperature.

For a spontaneous change,free energy change $\Delta G$ is

For the reaction $C_{(graphite)} + CO_{2(g)} \rightarrow 2CO_{(g)}$,$\Delta H = 170 \ kJ$ and $\Delta S = 170 \ J/K$. At what temperature $(K)$ will the reaction become spontaneous?