What is the oxidation number of cl - in the perchlorate ion, assuming the cl-o bonds are all single bonds?

The molecular formula for perchlorate ion is: ClO₄⁻

The oxidation number of oxygen, O = - 2

Let 'x' be the oxidation number of Cl-. Now the net charge on the system is - 1

i. e., Cl + 4 (O) = - 1

(x) + (4) (-2) = - 1

x = - 1 + 8 = + 7

Therefore, the oxidation number of Cl - in perchlorate ion is + 7