Chemistry - PERIODIC TABLE Question with Solution | TestHub

Concepts : Hess's Law; Born-Haber Cycle for oxides.

Solution:

$\Delta {\mathrm{H}}_{\mathrm{f}}=\Delta {\mathrm{H}}_{\text{sub }}+\left({\mathrm{IE}}_1+{\mathrm{IE}}_2\right)+\frac{1}{2}{\mathrm{D}}_{\mathrm{O}={\mathrm{O}}^{}}+\left(\Delta {\mathrm{H}}_{\text{eg }1}+\Delta {\mathrm{H}}_{\text{eg }2}\right)+\mathrm{U}$

For stability, $\Delta H_f<0$.

Given the values:

$0=150+2200+\frac{1}{2}(498)+650+U$

$0=150+2200+249+650+U$

$0=3249+U⟹U=-3249kJ/mol$

The magnitude of the lattice energy is $|U|>3249kJ/mol$.

Correct Answer: option B