What is the oxidation number of carbon in the ion (Co3)2-?

2 Answers
Oct 22, 2015

Answer:

The carbon is fully oxidized. Therefore, it is #C, IV^+#.

Explanation:

The sum of the formal oxidation numbers in an a complex or compound ion must sum to the charge of the ion. Here the charge is #-2#. Oxygen typically has an oxidation number of #-II#, and it does here. So #3 xx -2 + C_(ON) = -2#. And what therefore is #C_(ON)#?

What is the oxidation number of carbon in oxalate ion, #C_2O_4^(2-)#?

Answer:

The oxidation number of the carbon is +4.

Explanation:

Oxygen normally has an oxidation state of -2.

Oxygen = three ions each with a charge of -2 = 3 x -2 = -6
The overall charge of the polyatomic ion is -2

This means that the oxidation number of the carbon must be +4.

Total charge = +4 + -6 = -2

Here is a video which discusses this topic by discussing how to determine oxidation numbers of elements in the bicarbonate and dichromate ions.

Video from: Noel Pauller

Hope this helps!