Question

In the disproportionation reaction CI2 + H2Omc021-1.jpgHCIO + HCI, what describes the oxidation states of the substance Cl?

Answer 1

Reaction: CI2 + H2O    ---->  HCIO + HCI

Oxidations states:

The oxitation state of Cl2 = 0, because the oxidation state of an atom alone or a molucule with one kind of atom is always 0.

The oxidation state of Cl in HClO is +1 because the oxidation state of H is + 1, the oxidation state of O is - 2, and the molecule is neutral, so  +1 + 1 - 2 = 0

The oxidation state of Cl in HCl is - 1, because the oxidation state of H is +1 and the molecule is neutral, so - 1 + 1 = 0.

Also, you shall remember that when an atom increases its oxidation state is is oxidized and when an atoms reduces its oxidations state it is reduced.

With that you conclude that the right option is the last statement: Cl has an oxidation number of 0 in Cl2. It is then reduced to CI- with an oxidation number of –1 in HCl and is oxidized to Cl+ with an oxidation number +1 in HClO.