K2 Synthesis

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In all, based on the observations made throughout this part of the experiment and discussed in the results above, the confirmation of silver was justified since lead and silver each have distinct characteristics and unique responses that were expected to occur with each reagent. The observations that would have been made if lead was present, such as the critical formation of yellow precipitate when K2CrO4 was added, was negative. However, the results that were expected if silver was present were all justified with clear and evident results gathered throughout each step, and characterized based on insolubility, the formation of white precipitate when HNO3 was introduced, and the confirmed acidic solution.

PART B
With regards to Part B, once the initial two steps of this step were conducted, K2CrO4 was added. This reagent served to help identify whether Ca2+ or Ba2+ was present based on solubility and the presence of precipitate. On the principle of solubility, since the anion CrO42- forms mostly insoluble ionic compounds in water with most cations, Ca2+, could be identified due to that specific cation being one of the few exceptions.9 As a …show more content…

A false positive, an error that arises when the test results are positive even though the sample being studied is not present, could have occurred if the solution was cloudy prior to the addition of K2CrO4 and NH4OH.10 A cloudy solution meant that there was a possibility of contamination where remnants of precipitation that were examined in Part A still remained. These remnants, which could have held lead or silver would have posed a problem, especially if lead was suspended in the cloudy liquid, since Pb2+, like Ba2+, can react with K2CrO4, to form yellow precipitate. The consequence to this similarity would have resulted in a potential false positive with the cation in this step to be incorrectly identified as Ba2+ when it was actually mistaken for

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