<p>Oiram, I take it that the question is addressed to me, and not the OP.</p>
<p>An example of qualitative analysis would be that you’re given 10 different elements to study and you perform procedures to separate them from their compounds to confirm their presence. For example, a simple identification would be the confrimation from lead. You’re given a solution containing a combination of silver (I), mercury (II), and/or lead (II) or all of them. From previous experience, you understand that these cations can precipitate with chloride. So you add HCl which results in the precipitation of these compounds. Now you have precipitate of these compounds in your precipitate. Again, drawing from chemistry knowledge, you would know that if there were any PbCl2 in the solution (originally Pb), PbCl2 could be dissolved with hot water (though solubility for chlorides is always quite low. But PbCl2 has a higher solubility rate compared to Hg2Cl2 and AgCl). But dissolving the PbCl2 into a solution, you now can centrifuge the mixture of precipitate and PbCl2 solution and separate the two. To test for lead, in that solution, you would add acetic acid to break down the PbCl2 compound (if any), and then add potassium chromate to the solution. As potassium chromate is highly soluble, (most Group I elements are), the chromate will form a compound with the lead (II) and form lead chromate. Since this test is only good for lead (when compared to silver and mercury), if a yellow precipitate forms (characteristic of chromate compounds), then you know that lead is present (as lead is the only one which would form a precipitate given that Cl- and Pb2+ have been dissociated by the acetic acid). And that’s one of ten experiments in terms of qualitative analysis. And your grade is based on precision. How many elements you identify.</p>
<p>You conduct all those experiments from previous experience in other labs and of course the lecture. Using your knowledge of chemistry and experience in previous labs, qualitative analysis can be really fun and easy.</p>