Formula of metal oxide with metal deficiency defect in its crystal is A_ 0.8 O . The crystal contains A²⁺ and A³⁺ ions. The fraction of metal existing as A²⁺ ions in the crystal is

Step-by-step solution

A: O =0.8: 1=80: 100 Thus, if there are 100 O atoms, then number of A atoms =80 Charge on 100 O ²⁻ ions =100 (-2)=-200 Suppose number of A atoms present as A²⁺=x Number of A atoms present as A³⁺=80-x Total charge on A²⁺ and A³⁺=x (+2)+(80-x) (+3)=2 x+240-3 x=240-x As metal oxide is neutral, Total charge on cations = total charge on anions 240-x=200 or x=40 Fraction of metal existing as A²⁺ ions in the crystal =40 / 80=0.5