Qualitative analysis lab, zinc problem

will1530

1. The problem statement, all variables and given/known data

This is for a qualitative analysis lab. The unknown solution can contain any combination of the following ions: Na, Mg, Ni, Cr, Zn, Ag, Pb, NO3, Cl, I, SO4

Tools available: Bunsen burner for flame test, centrifuge, hot plate, and all the test tubes and DI water you could possibly want.

Chemicals available to add: The Na+ or NO3- solutions for all the above ions, HNO3, HCl, NH3, NaOH, saturated AgSO4 solution, and 18M H2SO4.


3. The attempt at a solution

I have been able to figure out any combination of the above except for zinc. In every other cation qual lab we've had a known number of cations and the strategy was to simply figure out all the cations you can and if you have an extra slot throw zinc into it and you'll be correct if you did everything else right. Now we have to figure out a way to test for zinc that won't be masked by any other cations. The only thing I can think of is to try to flame test for it, but that doesn't seem very practical in a bright lab with other ions potentially in solution.

chemisttree

What have you done to remove the other cations?