# big doubt



## arthur kierski (Feb 12, 2011)

i had a few grams (4,74) of black pgms powder cemented with iron from an ar solution-----this powder was calcinated in an oven at 500celsius and then put in a dilute sulfuric solution(hot) to eliminate any base metal---it became 4,02grams of black pgm (pd,pt,rh)------to the dilute h2so4 solution i did a test with stanous chloride and the test gave a red (purple ) collor---i deduced that the liquid might have rh or pt or even a mix of the three metals---by the collor i thought of rh-----to this tested sulfate solution i added a small piece of steel wool which dissolved and precipitated some powder----pt?rh?or a mixture?
please ,i would like some coments and sugestions
Arthur


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## Lou (Feb 12, 2011)

It's probably Rh. If you got a red stannous indication and the color of your solution is brown-yellow, it's likely rhodium.

You'd have been better served to use dilute HCl.


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## lazersteve (Feb 12, 2011)

Qualitative Chemical Analysis said:


> Alkali hydroxides or carbonates added to Rh solution should give yellow Rh(OH)3, insoluble in HCl, but soluble in excess NH4OH. The resulting solution can be filtered and HCl added to precipitate bright yellow Rh salt Rh(NH3)5Cl3.



Steve


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## arthur kierski (Feb 12, 2011)

Thanks,Steve and LOU----i will have much more of this powder and will repeat the experience with h2so4 and if it happens again ---i will go after the rh---i will not use dilute hcl because i want to repeat the experiment----


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