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

Correct Answer: 85

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%.