Question

The oxidation number of chlorine in \[NaCl{{O}_{3}}\] is:
a.) -5
b.) +2
c.) +5
d.) -3

Answer 1

Hint: Generally the oxidation number of an element is nothing but the number of valence electrons present in it. In ionic compounds oxidation number is the number of electrons gained or lost by the element. Chlorine shows an oxidation state of -1 due to the loss of one valence electron.

Complete step by step answer:
When an element gains electrons then the oxidation number of the element decreases. Then the process of gaining of electrons is called reduction.
If the element loses its electrons then the oxidation number of the element increases. Then the process of losing electrons is called oxidation.
Now come to the given question.
We have to calculate the oxidation number of chlorine in \[NaCl{{O}_{3}}\].
The number of sodium atoms in \[NaCl{{O}_{3}}\]is one, the number of chlorine atoms are one, and the number of oxygen atoms are three.
The oxidation state of oxygen is ‘-2’ and the oxidation state of sodium is ‘+1’.
The formula to calculate the oxidation number of chlorine is:
= Oxidation number of Sodium + Oxidation number of Chlorine + 3 (oxidation number of oxygen).
Oxidation state of chlorine = -[(1) + 3( -2)] = -(1- 6) = +5.
Therefore the oxidation state of chlorine in \[NaCl{{O}_{3}}\] is +5.
So, the correct answer is “Option C”.

Note: \[NaCl{{O}_{3}}\] is called sodium chlorate. It is an inorganic sodium salt. It is used in bleaching of paper and used as herbicide. \[NaCl{{O}_{3}}\] is used to prepare aromatic amino acids. Through disproportionation reaction (redox reaction) sodium chlorate is formed.