Question

What is an oxidation number or oxidation state? How is it useful to identify redox reactions, oxidant and reductant?

Answer 1

oxidation state is the charge present on atom of an element or compound.if oxidation state of any element or compound gets decreased after reaction ,then that very element is getting reductionized and vice versa about oxidation.

Answer 2

Answer:

Oxidation number or oxidation state : The oxidation number (or oxidation state) of an atom in a molecule or an ion is defined as the number of charges it would carry if the electrons were completely transferred.

Explanation:

(1) The oxidation number or oxidation state does not always imply ionic charges on the species.

(2) The oxidation number of monoatomic ion is equal to charge of the ion. For example, Na^+ has + 1 charge while Cl^- has 1 charge, Ca²^+ has +2 charge and so on (But the oxidation states are 1+, 1-, 2+ respectively).

(3) In case of a neutral molecule, the sum of the oxidation numbers of all the constituent atoms is always zero.

(4) The charge on a polyatomic ion is equal to the algebraic sum of the oxidation numbers of all the constituent atoms of the ion.

(5) From the change in the oxidation numbers in a redox reaction, an oxidant and a reductant can be identified.

[Note : Oxidation number or oxidation state is represented as 1+, 2+, etc. while charge is represented as +1, + 2, etc.)