Let the formula of the sample be `(Fe^(2+))_(x)(Fe^(3+))_(y)O`
On looking at the given formula of the compound
x+y=0.93
total positive charge on ferric ions should balance to two units os neagative charge on oxygen
therefore `2x+3y=2`
`implies x+(3)/(2) y=1`
On subtracting equation (i) from equation (iii) we have
`(3)/(2) y-y=1-0.93`
`implies (1)(2) y=0.07`
`implies y=0.14`
On putting the value of y in equation (i) we get
`x+0.14=0.93`
`implies x=0.93-0.14`
`implies x=0.79`
Fraction of `Fe^(2+)` ions present in the sample `=(0.79)/(0.93)=0.849`
Metal deficiency defect is present in the present in the sample becauses iron is less in amount than that required for stoichiometric compostion .
