For a certain reaction, $\Delta H^{\circ} = 40 \text{ kJ}$ and $\Delta S^{\circ} = 80 \text{ JK}^{-1}$. Find the temperature at which $\Delta G^{\circ} = 0$. (in $\text{ K}$)

When $\Delta H_{vap} = 30 \ kJ \ mol^{-1}$ and $\Delta S_{vap} = 75 \ J \ mol^{-1} \ K^{-1}$,then the temperature of vapour,at one atmosphere is . . . . $K$.

$2 \, mol$ of zinc is dissolved in $HCl$ at $25 \, ^\circ C$. The work done in an open vessel is: (in $, kJ$)

Compare the following criteria for spontaneity of a reaction based on the values of $\Delta_{\text{r}}H^0$,$\Delta_{\text{r}}S^0$,and $\Delta_{\text{r}}G^0$:

$\Delta_{\text{r}}H^0$	$\Delta_{\text{r}}S^0$	$\Delta_{\text{r}}G^0$	Description
$(a) (+)$	$(-)$	$(+)$	$(i) \text{ Non-spontaneous at all temperatures}$
$(b) (-)$	$(-)$	$(-)$	$(ii) \text{ Spontaneous at low temperatures}$
$(c) (-)$	$(+)$	$(-)$	$(iii) \text{ Spontaneous at all temperatures}$

For the conversion of limestone to lime,$CaCO_{3(s)} \rightarrow CaO_{(s)} + CO_{2(g)}$,the values of $\Delta H^{\circ}$ and $\Delta S^{\circ}$ at $298 \, K$ and $1 \, bar$ pressure are $+179.1 \, kJ \, mol^{-1}$ and $160.2 \, J \, K^{-1} \, mol^{-1}$ respectively. Assuming $\Delta H^{\circ}$ and $\Delta S^{\circ}$ do not change with temperature,at what temperature (in $K$) will the conversion of limestone to lime become spontaneous (in $, K$)?

Assertion: Many endothermic reactions that are not spontaneous at room temperature become spontaneous at high temperature.
Reason: Entropy of the system increases with increase in temperature.