Question #3c1e2

1 Answer
Jun 22, 2016

Answer:

You mean the oxidation number of #Co# in #"cobaltous chloride"#, #CoCl_2# is #+II#. Of course you may mean the oxidation state of inorganic #C# in phosgene gas, #Cl_2C(=O)#, which is #+IV#.

Explanation:

The oxidation number is the charge left on the central atom when all of the bonding species are removed from it. Chlorine binds here as the ion chloride, #Cl^-#. For a neutral molecule the sum of the oxidation numbers is zero:

#Co^("Oxidation number")-2xx1=0#

The halogens normally have a #-I# oxidation number.

Of course if you want the oxidation number of #C# in #Cl_2C=O# this is #+IV#.