For water ${\mathrm{\Delta }}_{\mathrm{vap} }\mathrm{H}=41 \mathrm{kJ}{ \mathrm{mol}}^{-1}$ at $373 \mathrm{K}$ and 1 bar pressure. Assuming that water vapour is an ideal gas that occupies a much larger volume than liquid water, the internal energy change during evaporation of water is $\left({\mathrm{kJmol}}^{-1}\right)$:
[ Use $\left.:\mathrm{R}=8.3 \mathrm{J}{ \mathrm{mol}}^{-1}{ \mathrm{K}}^{-1}\right]$

The Born-Haber cycle for $\mathrm{KCl}$ is evaluated with the following data:
${\mathrm{\Delta }}_f{\mathrm{H}}^{\mathrm{\Theta }}\text{ for }\mathrm{KCl}=-436.7{\mathrm{kJmol}}^{-1};{\mathrm{\Delta }}_{\mathrm{sub}}{\mathrm{H}}^{\mathrm{\Theta }}\text{ for }\mathrm{K}=89.2{\mathrm{kJmol}}^{-1};$

${\mathrm{\Delta }}_{\text{ionization }}{\mathrm{H}}^{\mathrm{\Theta }}\text{ for }\mathrm{K}=419.0\mathrm{kJ}{\text{ mol }}^{-1};{\mathrm{\Delta }}_{\text{electron gain }}{\mathrm{H}}^{\mathrm{\Theta }}\text{ for }{\mathrm{Cl}}_{\left(\mathrm{g}\right)}=-348.6{\mathrm{kJmol}}^{-1}$

${\mathrm{\Delta }}_{\text{bond }}{\mathrm{H}}^{\mathrm{\Theta }}\text{ for }{\mathrm{Cl}}_2=243.0{\mathrm{kJmol}}^{-1}$
The magnitude of lattice enthalpy of $\mathrm{KCl}$ in ${\mathrm{kJmol}}^{-1}$ is (Nearest integer)

[ Use $R=8.314 \mathrm{J} {\mathrm{mol}}^{-1} {\mathrm{K}}^{-1}$]

$3\mathrm{HC}\equiv {\mathrm{CH}}_{\left(\mathrm{g}\right)}\rightleftharpoons {\mathrm{C}}_6{\mathrm{H}}_{6\left(\mathrm{l}\right)}$

[Given: ${\mathrm{\Delta }}_{\mathrm{f}}\mathrm{G}°\left(\mathrm{HC}\equiv \mathrm{CH}\right)=-2.04\times {10}^5 \mathrm{J} {\mathrm{mol}}^{-1}; {\mathrm{\Delta }}_{\mathrm{f}}\mathrm{G}°\left({\mathrm{C}}_6{\mathrm{H}}_6\right)=-1.24\times {10}^5 \mathrm{J} {\mathrm{mol}}^{-1}; \mathrm{R}=8.314 \mathrm{J} {\mathrm{K}}^{-1} {\mathrm{mol}}^{-1}$]