Addition of `CdCl_(2)` to the crystals of AgCl will produce Schottky defects but the same is not produced when NaCl crystals are added. Discuss.

Explanation

When `CdCl_(2)` is added to the crystals of AgCl, the replacement of one `Ag^(+)` ion with `Cd^(2+)` ion necessitates the removal of second `Ag^(+)` ion from the lattice to maintain the electrical neutrality of the crystal. However, the same does not take place in case of NaCl because both `Ag^(+)` and `Na^(+)` ions are monovalent. Thus, Schottky defects are caused by the addition of `CdCl_(2)` and not by NaCl.