* Oxygen's usual oxidation state: Oxygen typically has an oxidation state of -2.

* Net charge of the molecule: ClO is a neutral molecule, so its overall charge is 0.

Let 'x' represent the oxidation state of Cl. We can set up the following equation:

x + (-2) = 0

Solving for x:

x = +2

Therefore, the oxidation state of Cl in ClO is +2.