Question

The Born-Haber cycle for formation of rubidium chloride ($RbCl$)is given below (the enthalpies are in $kCal$ ${mol}^{-1}$).
Find the value of $X$.

Answer 1

Heat of formotion = Heat of sublimation + Dessolution energy +Ionzation + energy + (electron affnutr+)

Substituting values

$\Delta H_f=\Delta H_S+\Delta H_D+\Delta IE+\Delta E_a+\Delta U$

$-105=+20.5+28.75+96.0+X-159.5$

$X=-90.75Kcel/mol$