Find out the oxidation number of chlorine in the following compounds and arrange them in increasing order of oxidation number of chlorine.
Oxidation number is calculated by assuming the unknown ON as x and applying the rules of oxidation number for the rest of the atom/molecules bonded with the unknown atom.
For all the chlorine atoms we assume its oxidation state as x, and for atoms Na, K = +1, O = -2. Thus by thumb rule of oxidation, the algebraic sum of oxidation numbers of all the atoms/molecules in a compound is equal to zero or to the charge on that compound for an ion.
The Cl2O7 structure is interesting to learn, as there are two atoms of chlorine atom with different kinds of O ─ O, Cl ─ Cl. Its structure is given as:
Ascending order of compounds w.r.t their oxidation number is:
NaCl (-1), Cl2(0), Cl2O(+1), KClO2(+3), ClO2(+4), NaClO3(+5), ClO3(+6), Cl2O7=NaClO4(+7).
Among the above compounds the oxidation number +2 is not present.