Question

A sample of wustite $F{{e}_{2}}O$ contains one Fe (III) for every three Fe(II). The value of X is:
(A).$\dfrac{9}{8}$
(B).$\dfrac{8}{9}$
(C).$\dfrac{3}{4}$
(D).$\dfrac{4}{3}$

Answer 1

Hint: Wustite is a mineral from the iron oxide which is found with meteorites and the native ion. Wustite is grey in color and has a greenish tint in the reflected light. Wustite has a hardness of 5 to 5.5 and specific gravity of around 5.88.

Complete answer:
The chemical formulae of wustite if FeO and the molecular weight is around 71.85 g.
Let there be 1 mole of iron atom so,
The amount of Fe (III) = $\dfrac{1}{4}$mole
The amount of Fe (II) = $\dfrac{3}{4}$ mole
Hence the total positive charge will be = $\dfrac{1}{4}(3)+\dfrac{3}{4}(2)=\dfrac{9}{4}$mol
The charge will be positive because iron is positive in the bonded state,
Let the number of oxygen atoms be x hence
The total negative charges = $(x)(2)$
The charge is negative because oxygen has a negative charge
So to satisfy the electroneutrality principle the total positive charges = total negative charges
\[\dfrac{9}{4}mol=2X\]
The value of X = $\dfrac{9}{8}$mol

Hence the correct answer is option (A) i.e. A sample of wustite $F{{e}_{2}}O$ contains one Fe (III) for every three Fe(II). The value of X is $\dfrac{9}{8}$mol.

Note:
Pauling’s principle of electronegativity states that each atom of a stable substance has the charge which is close to zero. This principle explains the structure which is adopted by hydrogen cyanide. It also explains the relative contribution of the resonance structures.
This principle explains the stability of complexes which means that the total negative charge in a compound will be equal to the total positive charge in a compound.