Question

The composition of a sample of Wurstite is $F{e}_{0.93}{O}_{1.00}$ . Percentage of iron present in the form of iron (III) is nearly:

• A. $85$
• B. $15$
• C. $7$
• D. $93$

Answer 1

Answer: (B)

$15$

Let the amount of Fe(II) be $x$ and Fe(III) be $y$.

It is given that $x+y=0.93$ and $2x+3y=2$ (Since the total negative charge is equal to the total positive charge in the empirical formula)

Solving them, we get $x=0.79$ and $y=0.14$

Percentage of Fe(III) $=\frac{0.14}{0.93}\times 100=15\%$