Qualitative analysis can determine the metal cations that are present in a sampl
ID: 826194 • Letter: Q
Question
Qualitative analysis can determine the metal cations that are present in a sample based on their solubility characteristics. One such scheme is shown in the flow diagram. Some ions that are soluble in all of the test solutions can still be identified based on flame tests. Certain ions impart characteristic color to the flame. Metal cation Flame color Li red Na yellow K purple Part A A solution contains some or all of the ions Cu2+, Al3+, K+, Ca2+, Ba2+, Pb2+, and NH4+. The following tests were performed, in order, on the solution. Addition of 6 M HCl produced no reaction. Addition of H2S with 0.2 M HCl produced a black solid. Addition of (NH4)2S produced a white solid. Addition of (NH4)2HPO4 in NH3 produced no reaction. The final supernatant when heated produced a purple flame. Identify which of these ions were present in the solution, which were absent, and for which ones no conclusions can be drawn. Drag the appropriate items to their respective bins.
Explanation / Answer
Present: cu2+, al3+,k+
absent: ca2+,pb2+,ba2+
inconsisive: nh4+