and black precipitate was formed Presence of Zn 2 was confirmed The equation of

And black precipitate was formed presence of zn 2 was

This preview shows page 15 - 27 out of 27 pages.

and black precipitate was formed. Presence of Zn 2+ was confirmed. The equation of the confirmatory test is 3Zn 2+ + 2Fe(CN) 6 4- Zn 3+ [Fe(CN) 6 ] 2 For the unknown mixture, no precipitate was formed when HCl was initially added to the sample. There is no presence of Ag + ion. The only 2 cations left are Cu 2+ and Zn 2+ which form soluble salt when reacted with HCl. When the identification reaction was proceed to procedure B, white precipitate was formed and it indicates the presence of Cu 2+ . When Cu 2+ react with H 2 S produced by thioacetamide added in acidic solution, insoluble sulfide salt,CuS was formed. Confirmatory test was carried out but no precipitate was formed when NH 3 was added. No precipitate was formed. The test was carried out further by K 4 Fe(CN) 6 and white precipitate was formed. The balanced chemical equation is 2Cu 2+ + Fe(CN) 6 4- Cu 2 [ Fe(CN) 6 ] For the identification of Zn 2+ ion, on adding H 2 S under basic condition,white precipitate was formed. The balanced chemical equation for the insoluble sulfide salt is Zn 2+ + S 2- ZnS But when further identification test was carried out using K 4 Fe(CN) 6 , no precipitate was formed. There is no presence of Zn 2+ . As a conclusion, unknown number II only contain Cu 2+ ion. For the two experiments, the acids used, HCl, H2SO4 and HNO3 are corrosive and can cause permanent damage to the skin and eyes. If the solution is in contact with the skin or the eyes, quickly wash with running water. Next, all the chemical used should be discarded into the chemical waste bottle provided. The precipitate should also go to the waste bottle, nothing should go into the sink.
Image of page 15
CONCLUSION The mixture contains the three transition metal, Cu 2+ , Ag + and Ca 2+ . Unknown number II only contain Cu 2+ ion. REFERENCES 1) Laboratory manual Hadariah Bahron, Kamariah Muda, Syarifah Rohaiza Syed Omar, Kamariah Kassim (2016). Inorganic Chemistry : Experiments for Undergraduates( 3 rd editon) 1-10. 2) Qualitative analysis to identify transition metal cations. (n.d.). Retrieved March 31, 2016, from ansition_metal_cations 3) Wired Chemist. (n.d.). Retrieved March 31, 2016, from - tutorials/qualitative-analysis
Image of page 16
DATA SHEET Experiment 1
Image of page 17
Image of page 18
Image of page 19
Experiment 2
Image of page 20
Image of page 21
Image of page 22
Image of page 23
Image of page 24
Image of page 25
Image of page 26
Image of page 27

You've reached the end of your free preview.

Want to read all 27 pages?

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture