Starting out the experiment, HCI was added to the solution in the test-tube in order to form a reaction between the HCI, Gag, BP, and Hug cautions. The products of this addition of HCI were Pubic, Gall, and Height. After the HCI was added, the solution turned a milky white color. It was important to not add too much HCI because excess HCI would have caused an aqueous complex of Pubic and Gall to form instead of the desired solid Pubic. The mixture was then centrifuged in order to let the solid particles of the three ions to fall to the bottom. Another rope of HCI was added to test if the reaction had been completed.
If the solution were to turn milky white again then it would’ve signaled an incomplete reaction between the cautions and HCI. The next objective was to separate the lead(al) ion from the mixture. The test tube with all three solids precipitated at the bottom was heated, which allowed the Pubic to dissolve. The supernatant fluid containing the BP(al) ions was then separated from the solid mercury(l) ions and solid silver ions decanting, adding a drop of acetic acid to the supernatant fluid, and also adding two drops of Kicker to the test tube.
A milky yellow mixture was observed as this indicated the presence of the lead (II) ion. This insoluble yellow precipitate was the insoluble compound of Picric. In part 2 of the experiment, after the supernatant liquid was separated and the drops of acetic acid and Kicker were added, the solution did not turn a milky white indicating the absence of lead (II) ions in the unknown. The next step was to display the mercury (I) ions present. NH was added to the test-tube with the saved white and grey precipitate. The mixture was then centrifuged and a grey precipitate as found at the bottom of the test-tube.
This grey participate signaled the presence of mercury (l) ion in the mixture. The compound that shows the presence of mercury (l) ion is Hogging. The unknown sample contained mercury (l) ions because of the observed precipitation of the grey substance to the bottom of the test tube after the addition of NH and centrifuging. Last but not least, the presence of silver ions had to be tested. One ml of nitric acid was added to the supernatant solution from the previous step in order to neutralize it and produce Gall salt.
Once the nitric acid was added, the solution turned a milky white color and white precipitate was observed floating around in solution. In the unknown, silver ions were present because of the observed white precipitate formed when adding nitric acid. More than one ml had to be added in order for the precipitate to be observed, so approximately 25 drops were added as opposed to 20(20 drops equals approximately one Although the experiment faced a couple minor problems, it went smoothly overall. One of these difficulties was a problem with one of the centrifuges.
I had set the timer o 3 minutes but it proceeded for a minute and then stopped. I had to in turn go and reset the timer. This technical difficulty was not a personal fault, just an equipment problem. Another problem faced was the rapid evaporation of the boiling water in the 250 ml beaker used to heat the initial test-tube. For part one of the experiment, there was sufficient water to heat the test-tube, but as part 2 came around, the water level had dropped sufficiently and the test-tube wasn’t able to be heated to its fullest potential. This could have affected the outcome of the visibility of lead(al) ions.