KEAM 2010 Physics and Chemistry Paper

In all the given species except ClO−, the central atoms are either in their minimum or maximum oxidation states and hence, they cannot further decrease or increase their oxidation states. In ClO−, the oxidation state of Cl can be increased or decreased when it acts as oxidising or reducing agents.

Species	Oxidation state
Cl−	−1
ClO4−	+7
ClO−	+1
MnO4−	+7
NO3−	+5