Find out the ratio of the mole-fraction of the Frenkel’s defect in $NaCl$ crystal at $4000\;K$ temperature. The amount of energy needed to form Frenkel’s defects and Schottky defects are respectively $2\;eV$ and $4\;eV$.

Question

$Note$: $1eV=1.6×10^{–19} \;V, \; k=1.23×10^{–23}$

$\begin{array}{1 1} 25.71:1 \\ 51.42 :1 \\ 12.85:1 \\ 22.35 :1 \end{array} $