What is the electron affinity of iodine(Kcal) based on the following data
a) sublimation energy of  $\mathrm{Na}=26\mathrm{Kcal}/\mathrm{mole}$
b) Bond energy of ${\mathrm{I}}_2=50\mathrm{Kcal}/\mathrm{mole}$
c) Ionisation enthalpy of $\mathrm{Na}=118\mathrm{Kcal}/\mathrm{mole}$
d) Lattice energy of $\mathrm{NaI}=-165\mathrm{Kcal}/\mathrm{mole}$
e) heat of formation of $\mathrm{NaI}=-69\mathrm{Kcal}/\mathrm{mole}$