86%(14)12 out of 14 people found this document helpful
This preview shows page 11 - 14 out of 15 pages.
iron was the precipitate and it was red, but nickel did change colors to a deep blue. These reactions were important because they decided what reagents to use for the overall goal to separate the cation solutions into precipitates later in the experiment. The steps done in table #2 were done to see what additional reagents should have been used to separate the rest of the
cations, specifically iron and nickel. Also, these steps compared the effect of these reagents in an acidic or basic solution to help justify which reagent can be used in each test tube that had either a basic or acidic solution in it later in the experiment. The results showed that 0.1M K4[Fe(CN)6]formed precipitates with nickel and iron in both basic and acidic solutions. Specifically though, 0.1M K4[Fe(CN)6] formed a dark/muddy red precipitate in a basic iron solution, and it formed a clear solution with a dark blue precipitate in the acidic iron solution. For 0.1M K4[Fe(CN)6] in nickel solution it formed a milky green precipitate in basic nickel solution and a turquoise precipitate in a yellow solution for the acidic nickel solution. For 0.1M DMG, it clearly made a bright pink precipitate with a basic nickel solution and no reaction happened in an acidic nickel solution. Also for 0.1M DMG there was no reaction in the acidic iron solution, and it was hard to tell whether a precipitate formed in the basic iron solution with a change in color of reddish brown. These reactions were important in the goal of separating the cations because it determined what reagents should be used and when they should be used in the flow chart in part three. Part 3: A flow chart was created in this part of the lab to separate the cation solutions with the reagents provided in the previous parts of the lab. Part 4: For part 4, a flow chart of an unknown solution E was made. First the reagent HCl was put into the unknown solution creating a white precipitate which showed that Ag+was present in the solution creating the precipitate AgCl (s). Next, in a fresh test tube the unknown solution was placed in it, and the reagent H2SO4was added which didn’t do anything visibly. Since nothing happened with the addition of sulfuric acid, it shows that there weren't any Ba2+ions present in the unknown solution because no precipitate was formed. Then, NH3was added
to the same test tube, and the solution turned blue which indicated that Ni2+cations could be present in the solution. This addition of ammonia also shows there weren't any Fe3+cations present because the solution didn’t form a red precipitate. To test this, DMG was added to the solution, and it turned pink which suggested that Ni2+ was indeed in the solution because it formed Ni(DMG)2(s). This showed that only Ag+and Ni2+were present in the unknown solution presented via flow chart.