What is the oxidation state?

Question

What are the oxidations sates of the transition metal ion in each of the following:
[Co(H20)6]^3+, [Cr(H2O)4(Cl)2], and [Os(NH3)2(Cl)2]SO4

Please help and explain!!!!

Answer 1

[Co(H20)6]^3+:
Oxidation state of the complex is +3, H2O has no charge, hence oxidation state of Co is +3 in this case.

[Cr(H2O)4(Cl)2]:
Oxidation state of the complex is 0, Cl has a -1 charge, H2O has no charge, hence the oxidation state of Cr, x:

x + 2(-1) +4(0) = 0 ------> Hence, x = +2

[Os(NH3)2(Cl)2]SO4
SO4 has a charge of -2, so the complex [Os(NH3)2(Cl)2]2+ has a charge of +2, such that the overall compound has no net charge. The charge on Cl is -1 and the charge of NH3 is 0, hence the oxidation state of Os, y:

y + 2(0) + 2(-1) = +2 -----> Hence, y = +4

Answer 2

Cobalt is +3 (Water is neutral, +3 outside charge), Chromium is +2 (chlorine has a -1 charge and water is neutral SO4/Sulphate is 2-), Osmium is +4 (Ammonia (NH3) has no charge cl = -2 and outside -2 as it is sulphate).

It's been a while since I have done that, I've checked the sulphate and ammonia and the nature of H2O is the hyrdogen and oxygen produce a neutral charge, likewise for the ammonia the 3 hydrogens cancel out the nitrogen.

Answer 3

Co is +3 the coordinated water molecules do not have charges.

Cr is +2 note that there are 2 chloride (-1) ions

Os is +4 same as Cr and it neutralizes the -2 sulfate ions.and 2 chloride (-1) ions

Answer 4

ok lets take up the first complex
the charge of each ligand, that is water molecule, is 0
and the overall charge of complex is 3
let the oxidation no of Co be x
then x +6.0 =3
therefore x is 3
in second complex
x +4.0 -2.1 =0
x =2
in the third complex
x +3.0 -2.1=2
x = 4

Answer 5

Florida is the oxidation state...things rust here.