# Inorganic Chemistry help

1. Apr 14, 2014

### utkarshakash

1. The problem statement, all variables and given/known data
A solution consist of Co+2 and Ni+2 ion in which excess KCN is added and in the resulting solution alkaline Br2 was added. The solution finally consist of which species?

3. The attempt at a solution

I guess some complex would be formed but how to exactly find out the complex? I don't have any idea as this does not involve any equations or mathematical approach. Any ideas?

2. Apr 15, 2014

### Pranav-Arora

Are there any options with the problem?

As you noticed, a complex should form in both the cases, the metal in the complex bears the same oxidation state as before.

Addition of alkaline $Br_2$ (which is basically $OBr^{-}$) serves as a test to differentiate between the two complexes. $Ni(OH)_3$ precipitates but the cobalt stays in the complex form.

3. Apr 15, 2014

### utkarshakash

The answer is K3[Co(CN)6] and Ni2O3. Why Co+2 has been oxidised to Co+3 and how did Ni2O3 appear?