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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Urbanium on March 11, 2015, 09:19:50 AM

Title: Exam question (isolation)
Post by: Urbanium on March 11, 2015, 09:19:50 AM
In one recent example of the Inorganic chemistry exam, there was a task asking approximately "what would be the easiest way in number of steps to isolate platinum from potassium hexacyanoplatinate"?

I wasn't quite sure about the answer, I think I would try to do some ligand exchange and then try to precipitate a hydroxyde, heat it to get the oxide and then reduce with e.g. coal to get the metal out. But it seems it takes too many steps. Any wise suggestion?
Title: Re: Exam question (isolation)
Post by: Hunter2 on March 11, 2015, 09:22:39 AM
I think adding of magnesium or zinc would do a reduction.
Title: Re: Exam question (isolation)
Post by: Borek on March 11, 2015, 04:47:30 PM
I would try roasting in the air.
Title: Re: Exam question (isolation)
Post by: Urbanium on March 12, 2015, 06:56:28 AM
One thing came up to my mind: what about the electrolysis of potassium hexacyanoplatinate?

Quote from: Hunter2 on March 11, 2015, 09:22:39 AM
I think adding of magnesium or zinc would do a reduction.

Directly to the hexacyanoplatinate solution?

Quote from: Borek on March 11, 2015, 04:47:30 PM
I would try roasting in the air.

The initial hexacyanoplatinate? Wouldn't that give an oxide?
Title: Re: Exam question (isolation)
Post by: Hunter2 on March 12, 2015, 07:10:25 AM
Electrolysis: Check where is your platinum cation or anion?

Yes directly to the hexacyanoplatinate solution.

The oxidation by roastin gwill give the metall platinum and potassiumoxid/carbonate probably, what can be washed away later on.

Title: Re: Exam question (isolation)
Post by: Borek on March 12, 2015, 08:57:58 AM
Don't forget potassium hexacyanoplatinate is weakly soluble, so wet chemistry can be challenging.
Title: Re: Exam question (isolation)
Post by: Urbanium on March 23, 2015, 11:21:28 AM
Update:

the exam went mostly fine. When it comes to the platinum group complexes, the example was not the former hexacyanoplatinate but potassium (II) tetrachloroplatinate.

How would you isolate Pt from that one with least steps possible?

I assume that roasting in the air would not work? I read that this complex is soluble in water. Could Mg or Zn do the reduction, or some other approach with small number of steps is better?
Title: Re: Exam question (isolation)
Post by: Urbanium on March 30, 2015, 11:17:52 AM
Anyone?
Title: Re: Exam question (isolation)
Post by: unsu on March 31, 2015, 02:43:05 AM
Draft ideas:

K2[PtCl4] + H2 = Pt + 2KCl + 2HCl (~200 °C)

K2[PtCl4] + H[SnCl3] + HCl(conc) = Pt + H2[SnCl6] + 2KCl

K2[PtCl4] + HCOOK = Pt + CO2 + 3KCl + HCl
Title: Re: Exam question (isolation)
Post by: Arkcon on March 31, 2015, 07:01:11 AM
Quote from: Urbanium on March 12, 2015, 06:56:28 AM
The initial hexacyanoplatinate? Wouldn't that give an oxide?

Platinum oxide?  No, that's not how its made: http://en.wikipedia.org/wiki/Adams%27s_catalyst