Qualitative Test for Some Cations I
(The Silver Group)
At the end of the class the student should be able to:
Separate, detect and identify the ions in a given unknown solution possibly containing the ions of the silver group. 2.
Identify the substance responsible for the positive result of each test 3.
Point out the suitable conditions necessary for the detection process and the reasons for such conditions Introduction
3 test tube labeled 1,2,3 was obtained
10 drops of 0.3M lead nitrate solution was placed to TT 1 3.
10 drops of 0.5M silver nitrate solution was placed to TT 2 4.
10 drops of 0.5 mercurous nitrate solution was placed to TT 3 5.
One drop of cold. 6N HCl solution was added to each TT. When precipitate forms, the HCl solution was continue to add in each TT drop by drop until no precipitate was form 6.
The precipitate was settled down and the supernatant liquid was decant 7.
The precipitate in the TT was added with 10 drops of distilled water, heated and shake 8.
5 drops of potassium chromate on the solution was added to TT 1 9.
10 drops of 6N ammonium hydroxide was added to TT 2 and 3 10.
6N HNO3 was added to TT 2
The precipitate in step 10 was placed in a container
Result (data sheet)
Exercise 19 “Qualitative Test for some Cations 1”. For this exercise we obtained 3 test tube, each test tube was treated with different reagent (6N HCl, hot H2O, K2CrO4, 6N NH4OH, 6N HNO3). TT 1,2 and 3 with reagent treatment 6N form a white precipitate, TT 1 with hot H2O was dissolved and color orange while TT 2 and 3 was undissolved. For reagent treatment K2CrO4, TT 1 form yellow precipitate, TT 2 treated with 6N NH4OH was dissolved while on TT 3 it form black precipitate. Lastly, for TT 2 treated with 6N HNO3. The role of n6N HCl solution is to form precipitate. Substances formed when 6N HCl was added to TT1 is PbCl2
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