Question

Metal deficiency defect is shown by $Fe_{0.93}O$. In the crystal, some $Fe^{2+}$ cations are missing and loss of positive charge is compensated by the presence of $Fe^{3+}$ ions. The percentage of $Fe^{2+}$ ions in the $Fe_{0.93}O$ crystals is ______ . (Nearest integer)

Answer 1

Let the number of $O^{–2}$ ions be $100$
and the number of $Fe^{+2}$ ions be $X$
The number of $Fe^{+3}$ ions be $(93 – X)$
$∴ X(2) + (93 – X)3 = 200$
$279 – X = 200$
$X = 279-200$
$X = 79$
∴ % of $Fe^{+2}$ ions$=\frac {79}{93}×100$
≃ 85%

So, the answer is 85%.