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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Michael on March 07, 2005, 08:40:57 PM

Title: Cation tests
Post by: Michael on March 07, 2005, 08:40:57 PM

Well you are testing for these cations by using:

1) NaOH (aq) first dropwise then in excess
2) NH3 (aq) first dropwise then in excess
3) KI (aq)

And you are testing for Pb, Ca and Cu and Fe
What would these do to the 4 cations?
Any colour changes or odours or other observations?

I found that

NaOH and Cu gives a Blue ppt turning black on heating
NH3 and Cu gives a Blue ppt turning deep blue in excess

NaOH and Fe gives A dirty green ppt turning brown on exposure to air and insoluble  to excess.
NH3 and Fe gives a dirty green ppt and turns brown in air insoluble in excess.
KI i don't know what it gives.

The rest i can't seem to find especially the KI tests.

Thanks for any help.

Title: Re:Cation tests
Post by: kevins on March 08, 2005, 11:09:23 AM

KI is used for the test of Pb, you know PbI2 is a ppt.

Please try the rest.

Title: Re:Cation tests
Post by: anh nguyen on April 28, 2005, 12:19:12 PM

HI how can u reconige Ni+2 Fe+3 and Mn +2

Title: Re:Cation tests
Post by: anh nguyen on April 28, 2005, 12:20:47 PM

Quote from: anh nguyen on April 28, 2005, 12:19:12 PM

HI how can u reconige Ni+2 Fe+3 and Mn +2