Question

Oxidation number of Oxygen in $F{e}_2{O}_3$

Answer 1

Hint: Oxidation number can be described as the number which is allocated to elements in a chemical combination. This number is the count of electrons such that the atoms in a molecule can share, lose, or gain while forming chemical bonds with other atoms of a different element.

Complete step by step solution:
-The oxidation number of an atom can be defined as the charge that an atom appears to have on forming ionic bonds with different atoms.
-Finding the oxidation number of an atom:
The oxidation state of an atom is the number of electrons in an atom that molecule has gained or lost compared to a neutral atom. The electropositive atoms, the group I, II, III elements exhibit constant positive oxidation numbers.
-More electronegative atoms gain electrons from the less electronegative atom in a molecule and exhibit negative oxidation states and the numerical value of the oxidation state is equal to the number of electrons lost or gained.
-The oxidation number of an atom in a molecule is assigned by:
(i) Adding the constant oxidation state of other atoms or molecules or ions which are bonded.
(ii) The total oxidation state of a molecule or ion equal to the total charge of the molecule or ion. Given molecule, calculating the oxidation number of Oxygen in $F{e}_2{O}_3$
The total charge of given molecule = 0
Oxidation state of $F{e}_2{O}_3$ = $2\times oxidationstateofFe+3\times oxidationstateofoxygen$ = 0
Oxidation state of Fe = +3
Let the oxidation number of oxygen = x
Then, 0 = $2\times 3+3x$
x = -2

Hence, Oxidation number of Oxygen in $$F{e}_2{O}_3$$ is -2.

Note: If a reaction is an oxidation an increase in oxidation state and if the reaction is reduction a decrease in oxidation state. Without the use of electron half-reactions in redox reactions, the change in the oxidation state of an element determines if it is oxidized or reduced.