Ni2+(aq) + DMG Bright pink colored complex - Eq(3)This experiment was conducted smoothly and the correct cations were identified in the given unknown sample. However, there are various sources of errors that could have occurred during the course of this experiment. While separating the precipitate from the solution by centrifugation, the contents may not have been separated completely which would have resulted in accurate spot test results and an error in the identification of the correct cations. Also, while conducting the spot tests, contamination of the spot plate or test tubes due to improper cleaning may have given wrong results. In order to minimize these errors, the equipment used should be cleaned properly and multiple trials should be conducted. Conclusion:Qualitative analysis focuses on the presence of a specific element or ion and not the amount. In this experiment, Lead and Nickel were the cations identified in the unknown sample (#66) using the Cation Analysis scheme that was constructed based on the results and observations from the separations, spot tests and flame tests. Contamination of equipment is one of the major errors in this experiment that can be minimized by proper cleaning and usage of equipment.