Question

Calculate the oxidation state of chromium (Cr) in CrO4
2-.

Answer 1

Answer:

I suppose the question should be what the oxidation state of Cr in chromate, CrO4^2-

Oxidation state of O is 2-, 4 O's makes 8-

(Oxidation state of Cr) + ( 8-) must equal 2-, hence oxidation state of Cr can only be 6+

Remember the sum of oxidation states in a ion always equals the electric charge of the ion

OR

I assume Cro4(2-) has been written in the way because cr can have +6 as its maximum oxidation state..

So let the oxidation state of cr be x and o Carries -2 charge

X+(-2*4)=-2

X-8=-2

X=+6

Cr has +6 oxidation state