3(aq) added, stirred , cooled and centrifuged. Then, the supernatant is saved for part C. 10-12 drops of 3M KOH and 5-6 drops of .1M tin (II) chloride were added. A black Precipitate is not formed, indicates that there is no Bi +3 in the original sample. The supernatant saved for part C was divided in to two. To one of the sample 10-12 drops of 6M acetic acid 5-6 drops of 0.2 M K 4 Fe(CN) 6 was added. No appearance of reddish/brown precipitate of Cu 2 Fe(CN) 6 was formed confirms that, no Cu +2 in the original sample.
To the second sample 1ml of 10% thiocetamide was added and heated for 2-3minutse in the boiling water bath. No yellow precipitate of CdS was observed, this shows no Cd +2 in the original sample. Project C: Confirmed ions: Zn +2 Confirmation Tests: The solution saved in project B became basic buffer by adding 6M of NH 3 . Then 20-25 drops of 10 % thioacetamide solution was added, stirred and heated in a boiling water bath for 5-10 minutes. This hydrolysis the thioacetamide and grayish white precipitate was formed. Then, centrifuged and the supernatant was saved for project D. The precipitate of the Group III sulfide was treated by 25-30 drops of 6M HCl. Stirred and heated in the boiling water bath for 10 minutes. During the heating process all the precipitate dissolved , no black solid left, so no confirmation test was done . This confirms no CO +2 and Ni +2 was present in the original sample.
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- Spring '10
- NH3, original sample, precipitate, centrifuged, 6M acetic acid