For the reaction $2Cl_{(g)} \rightarrow Cl_{2(g)}$,the signs of $\Delta H$ and $\Delta S$ are respectively:

When $1 \ g$ equivalent of a strong acid reacts with a strong base,the heat released is $13.5 \ kcal$. When $1 \ g$ equivalent of $H_2A$ is completely neutralized against a strong base,$13 \ kcal$ is released. When $1 \ g$ equivalent of $B(OH)_2$ is completely neutralized against a strong acid,$10 \ kcal$ of heat is released. Calculate the enthalpy change when $1 \ mole$ of $H_2A$ is completely neutralized by $B(OH)_2$ in $kcal$.

Match the following:

$(a)$ Entropy of vaporization	$(1)$ Decreases
$(b)$ $K$ for spontaneous process	$(2)$ Always has a $(+)$ value
$(c)$ Crystalline solid state	$(3)$ Has minimum entropy
$(d)$ $\Delta U$ for adiabatic expansion of an ideal gas	$(4)$ $\frac{\Delta H_{vap}}{T_b}$

The standard molar enthalpies of formation for ethane,$CO_2$,and water $(l)$ are $-21.1$,$-94.1$,and $-68.3 \text{ kcal/mol}$ respectively. What is the standard molar enthalpy of combustion for ethane in $\text{kcal/mol}$?

One mole of an ideal monoatomic gas at temperature $T$ expands adiabatically in an insulated flask from $1 \ L$ to $2 \ L$ against an external pressure of $1 \ atm$. What is the final temperature?

For an ideal gas, consider only $P-V$ work in going from an initial state $X$ to the final state $Z$. The final state $Z$ can be reached by either of the two paths shown in the figure. Which of the following choice(s) is (are) correct? [take $\Delta S$ as change in entropy and $w$ as work done].
(A) $\Delta S_{X \to Z} = \Delta S_{X \to Y} + \Delta S_{Y \to Z}$
(B) $w_{X \to Z} = w_{X \to Y} + w_{Y \to Z}$
(C) $w_{X \to Y \to Z} = w_{X \to Y} + w_{Y \to Z}$
(D) $\Delta S_{X \to Y \to Z} = \Delta S_{X \to Y}$