Lab 204 Qualitative Analysis Of Cations
H 204 – Introduction to Chemical Practice
Experiment # 1– Qualitative Analysis of Cations
Rachel Sorrells
Gretchen Diede
TA: Kunal Punjabi
February 16, 2017
RESULTS & DISCUSSION The purpose of this experiment was to utilize two different methods of qualitative analysis to determine the identity of two unknown cations in an unknown solution. The experiment required knowledge of solubility rules and demonstration of such in the laboratory setting for the first method of qualitative analysis. The second method of qualitative analysis was the performance of a flame test on various solutions to prove the presence of certain ions based on the color of the flame.
In this experiment, unknown solution #1 was proven to contain lead (Pb2+) and barium …show more content…
Chlorine is soluble unless it is bonded with silver, lead, or mercury, so this led the precipitate formed to definitively contain either lead chloride or silver chloride. The formation of a precipitate (either AgCl or PbCl2) was expected, which allowed the remaining liquid, containing either barium chloride or calcium chloride, to be separated and set aside into another test tube to be tested in Part B. The precipitate could then be further tested by mixing in potassium chromate to see if a yellow precipitate would form. A yellow precipitate would indicate that lead had bonded with chromate, which was the case for unknown solution …show more content…
Ammonium hydroxide and ammonium carbonate were added, and the test tube was placed in a warm water bath. The solution had to not be cloudy to proceed to the next step, and it took about two minutes for the solution to appear not cloudy. Ammonium hydroxide and potassium chromate were then added, and because the precipitate could not yet confirm which ion was present, hydrogen sulfate was added. A white precipitate was formed from the barium cation bonding with the chromate. The presence of this white precipitate confirmed the presence of Barium in unknown solution 1, which was reasonable because a barium and chromate compound is not soluble. If this experiment were to be repeated, a helpful change would be clarifying the instructions for Part B. The directions for steps 11-14 are vague, which led to confusion in step 11 when waiting for the solution to no longer appear cloudy. The step should explain why students must wait and what should be done
Experiment # 1– Qualitative Analysis of Cations
Rachel Sorrells
Gretchen Diede
TA: Kunal Punjabi
February 16, 2017
RESULTS & DISCUSSION The purpose of this experiment was to utilize two different methods of qualitative analysis to determine the identity of two unknown cations in an unknown solution. The experiment required knowledge of solubility rules and demonstration of such in the laboratory setting for the first method of qualitative analysis. The second method of qualitative analysis was the performance of a flame test on various solutions to prove the presence of certain ions based on the color of the flame.
In this experiment, unknown solution #1 was proven to contain lead (Pb2+) and barium …show more content…
Chlorine is soluble unless it is bonded with silver, lead, or mercury, so this led the precipitate formed to definitively contain either lead chloride or silver chloride. The formation of a precipitate (either AgCl or PbCl2) was expected, which allowed the remaining liquid, containing either barium chloride or calcium chloride, to be separated and set aside into another test tube to be tested in Part B. The precipitate could then be further tested by mixing in potassium chromate to see if a yellow precipitate would form. A yellow precipitate would indicate that lead had bonded with chromate, which was the case for unknown solution …show more content…
Ammonium hydroxide and ammonium carbonate were added, and the test tube was placed in a warm water bath. The solution had to not be cloudy to proceed to the next step, and it took about two minutes for the solution to appear not cloudy. Ammonium hydroxide and potassium chromate were then added, and because the precipitate could not yet confirm which ion was present, hydrogen sulfate was added. A white precipitate was formed from the barium cation bonding with the chromate. The presence of this white precipitate confirmed the presence of Barium in unknown solution 1, which was reasonable because a barium and chromate compound is not soluble. If this experiment were to be repeated, a helpful change would be clarifying the instructions for Part B. The directions for steps 11-14 are vague, which led to confusion in step 11 when waiting for the solution to no longer appear cloudy. The step should explain why students must wait and what should be done