In this experiment, qualitative analysis will once again be used to identify the unknowns present in a solution. However, today the unknown will contain ions from both Q-1 and Q-3 experiments. As before, the analysis will first be carried out on a known solution prepared by the student, and after this, an unknown solution from the professor will be analyzed.
The objective of this experiment is to take what you learned in the Q-1 and Q-3 experiments and apply that to complete your own analysis of ions from both experiments. In this experiment you will analyze known and unknown solutions. There will be no analysis of the unknown crystalssince you have already explored the presence of all Q-1 and Q-3 ions in the crystals.
Design a flowchart that combines both Q-1 and Q-3 so that any combination of the unknown ions can be identified. Do not include any unnecessary steps and try to keep the scheme as simple as possible.
You should NOT limit yourself to the standard procedures used in Q-1 and Q-3, but take advantage of any chemical properties (such as complexes and precipitates) that facilitate separation and identification. Indicate on your flowchart all reagents that are used and species that are formed.
In making your flowchart refer back to the schemes for Q-1 and Q-3 which can be found on pages 30 and 42 or in Appendix I. Also, refer to additional information on the chemistry of all of the ions on page 90 of Appendix I.
When listing Step Numbers on the flow chart, use the notation Q1-2 if you are using step 2 from the Q-1 analysis. If you are using a test that has not been previously listed, use an X before the step number. The procedure for any such “X test” must be included in your notebook.
After your scheme has been approved by your instructor, test it using a mixture containing 3 drops of each known solution. The observations for these tests are to be recorded on your known flow chart.
When confident of your scheme and technique, request an unknown from your lab assistant which will contain no more than 5 unknown ions. Starting with the specified number of drops of the unknown (NOT the entire amount that you are given) in lab manual, determine which ions are in the solution by recording your analysis on the unknown flow chart. Save the remaining portion of the unknown until your results have been approved.
When you have completed the analysis of the unknown, summarize your results and report to your instructor as soon as possible. Your instructor will then give you some feedback on your lab report.