FACULTY OF APPLIED SCIENCE CHM474 AS202 TITLE OF EXPERIMENT : ( 1 ) Qualitative Analysis For Identification Of metal Cations. ( 2 ) Qualitative Analysis of Transition Metal Cations: Ag + , Cu 2+ and Zn 2+ NAME : AINUL HANAN BINTI MAT ZAINI MATRIC ID : 2017411872 LAB’S PARTNER : NUR IRDINA SYAHIRAH BINTI ABDUL GHANI LAB’S MATRIC ID : 2017411818 GROUP : AS2022M1 LECTURER : DR LIM YING CHIN DATE OF EXPERIMENT : 29 MARCH 2018 DATE OF SUBMITION : 8 APRIL 2018 INTRODUCTION:
The purpose of this experiment is to identify the metal cations by perform the qualitative analysis. Based on the chemical and physically behavior, shows that the metal cations can be classified as five groups. One of group is analytical group I cations such as Ag + , Hg + and Pb 2+ ions. To identify this group, it will have formed precipitated when adding HCl in the solution. Then, Analytical group II cations such as As 3+ , Bi 3+ , Cd 3+ , Hg + , Cu 2+ , Pb 2+ and Sn 4+ ions. For this cation, it will form precipitated when react with H 2 S in acidic condition. Last but not least, the third group is Analytical group III cations such as Co 3+ , Fe 2+ , Mn 2+ , Ni 2+ , Zn 2+ , Al 3+ and Cr 3+ ions. Then, from this it will have a positive presence of metal cations when the solutions were adding with H 2 S in NH 3. OBJECTIVES: The purpose of this experiment is to perform qualitative analysis to identify metal cations. CHEMICAL AND APPARATUS: mixture of metal cations test tubes unknown sample I test tube holder unknown sample II test tube rack 6M hydrochloric acid, HCl centrifuge 6M ammonia, NH 3 glass rod 1M thioacetamide litmus paper Ammonium carbonate, (NH 4 ) 2 CO 3 water bath 6M acetic acid, CH 3 COOH 1M potassium chromate, K 2 CrO 4 1M potassium oxalate, K 2 C 2 O 4 6M nitric acid, HNO 3 0.1M potassium ferrocyanide, K 4 Fe(CN) 6 Distilled water. PROCEDURE:
EXPERIMENT 1 Procedure A 2 drops of 6 M HCl was added to 1 mL of the mixture of the metal cations. If the precipitate is formed, the suspensions was centrifuge for 1 minutes. 1 additional drop of 6M HCl was added to the clear supernatant to check for complete precipitation. If precipitate is observed in the supernatant, again the solution was centrifuge for 1 minutes. Procedure B 6 M NH 3 was added dropwise to the solution until basic. The sample was put in a boiling water bath for 2-3 minutes to remove the excess NH 3 . The volume of the solution was adjusted to 2 mL with distilled water and 10 drops of 6 M HCl was added. 12 drops of thioacetamide was added to the solution and was stirred. The sample was heated in a boiling water bath for 10 minutes to allow the hydrolysis of thioacetamide producing H 2 S. if precipitate of sulphide is formed, the mixture was centrifuge for 2 minutes. The supernatant was decanted to a clean test tube. The supernatant was saved for procedure C. Procedure C To the supernatant, 3 additional drops of 1 M thioacetamide was added and was reheated for 5 more minutes to test for complete precipitation. If precipitate is formed, the supernatant was centrifuged and decanted into a clean test tube and the precipitate was discarded. The volume of the
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