# What is the oxidation number of chlorine atom in HCl, Cl_2, and HClO?

In $H C l$ we have $C l \left(- I\right)$.............
In $C {l}_{2}$, $C l \left(0\right)$, and in $H C l O$, $C l \left(+ I\right)$.
For a homonuclear diatomic molecules, each atom has EQUAL electronegativity, and the charge is assumed to be shared; i.e. $C {l}_{2} \rightarrow 2 \times C l \cdot$; $H C l \rightarrow {H}^{+} + C {l}^{-}$; $H C l O \rightarrow {H}^{+ I} + C {l}^{+ I} + {O}^{+ I I}$.