The enthalpy of formation of $H_2O$ is $-68 \ k.cal/mol$. Calculate the enthalpy of formation of $OH^-$. Given that the enthalpy of neutralization of $H^+$ and $OH^-$ is $-13.7 \ k.cal/mol$.

$A$ fish swimming in a water body,when taken out,is covered with a film of water of weight $36 \ g$. When it is subjected to cooking at $100^{\circ} C$,the internal energy change for vaporization in $kJ \ mol^{-1}$ is $......$ [nearest integer].
[Assume steam to be an ideal gas. Given $\Delta_{vap} H^{\ominus}$ for water at $373 \ K$ and $1 \ bar$ is $41.1 \ kJ \ mol^{-1}$; $R = 8.31 \ J \ K^{-1} \ mol^{-1}$]

Consider the following statements:
$(A)$ Entropy of a perfect crystalline solid at absolute zero approaches zero.
$(B)$ For spontaneity of a reaction at constant temperature and pressure, $T\Delta S > \Delta H$ (where $\Delta H$ is positive).
Identify the correct answer from the options given below.

For isothermal expansion of an ideal gas, the correct combination of the thermodynamic parameters will be

In an irreversible process taking place at constant $T$ and $P$ and in which only pressure-volume work is being done,the change in Gibbs free energy $(dG)$ and change in entropy $(dS)$ satisfy the criteria:

$\Delta H$ and $\Delta E$ for the reaction,$Fe_{2}O_{3(s)} + 3H_{2(g)} \rightarrow 2Fe_{(s)} + 3H_{2}O_{(l)}$ at constant temperature are related as