Question

What is the oxidation state $Cl$ of a perchlorate ion, $Cl{O_4}^{ - 1}$ ?

Answer 1

The oxidation state of an atom depicts to us the number of electrons it has lost or gained to form a bond with another atom. Oxidation state thus represents the charge of the atom when it gets isolated from the compound. We will find the oxidation state of the chlorine atom in $Cl{O_4}^{ - 1}$ by writing the algebraic equation.

Complete Step By Step Answer:
The oxidation state of an atom refers to the charge of an atom when it accepts or loses electrons while making bonds with atoms. Oxidation state is the charge left on the atom when all of its bonded atoms are removed from the compound. The oxidation state of an atom can be found by using the algebraic expression which is the sum of oxidation states of all atoms equal to net charge on the compound. Thus for perchlorate ion $Cl{O_4}^{ - 1}$ , the oxidation state of chlorine can be found by using the algebraic expression of the sum of oxidation states of all atoms. Let x be the oxidation state of chlorine in perchlorate then it can be find as:
$\Rightarrow x + \left( {4 \times \left( { - 2} \right)} \right) = - 1$
$\Rightarrow x - 8 = - 1$
$\Rightarrow x = + 7$
Thus the oxidation state of chlorine atoms in perchlorate ions is $+ 7$ .

Note:
Sometimes oxidation refers to the oxidation number. It must be noted that the oxidation state of an atom can never be a fractional number. If it comes to be a fractional number then we can find the oxidation state by using the structure of the compound. The oxidation of chlorine thus varies from $- 7$ to $+ 7$ . It cannot be greater than $+ 7$ and cannot be less than $- 7$ . It is always an integer.