Name of the lab report: Introduction to Qualitative Analysis Pre-lab
Student’s name:
Panther ID:
CHM1045L
TA name:
Purpose:
This experiment explores how silver, lead (II), nickel, barium, and iron (III) ions interact with
different reagents and observes reactions, including the formation of precipitates and color
changes, ions can be identified. Furthermore, the experiment seeks to develop a flowchart
that outlines the confirmatory tests for analyzing unknown samples containing these cations
and provides a structured approach to identifying the ions present in unknown samples.
Procedure:
The experiment commenced with the washing and labeling of five test tubes for each ion
under investigation: silver, lead (II), nickel, barium, and iron (III). Following this, a sequence
of chemical tests was initiated on each test solution, starting with the addition of sulfate using
dropper bottles to dispense precisely 20 drops of the test solutions into their respective
labeled test tubes. Subsequently, 10 drops of 3 M H2SO4 were added to each test tube, and
observations were recorded for any resulting precipitates or color changes in Data Table 1.
Upon the formation of precipitates, the samples were carefully mixed with a clean stirring rod
and subjected to centrifugation. Once the observations were recorded, both the solutions and
precipitated were discarded.
, For the addition of HCl, 20 drops of the test solution were added to each labeled test tube,
followed by the addition of 10 drops of 6 M HCl. Upon the formation of the precipitate, the
samples were mixed with a clean stirring rod and subjected to centrifugation. Following
centrifugation, the supernatant was discarded, and the precipitant was washed twice with 1
mL of deionized water each time, ensuring the removal of any remaining supernatant.
The next steps involved the heating of precipitates and the addition of K2CrO4. The
precipitate formed in Test 2 was treated and 4mL of deionized water to the test tubes was
added, ensuring thorough mixing of the solutions. The test tubes with precipitate were placed
in a hot water bath for 5 minutes, with frequent stirring to ensure proper dissolution. The test
tubes were then subjected to centrifugation and the supernatant from each sample was poured
into a clean test tube. Subsequently, 2 drops of K2CrO4 were added to the hot liquid, and
observations were recorded in Data Table 1 followed by the remaining supernatants being
discarded.
For the addition of NaOH, 20 drops of the test solutions were added to clean test tubes
followed by the addition of 4 drops of 6 M NaOH. In the event of precipitate formation, the
sample was mixed, and centrifugation was performed. Observations were recorded in Data
Table 5. Upon completion of centrifugation, the supernatant was discarded and the precipitate
was washed twice with deionized water.
Finally, 20 drops of 15 M NH3 were added to each test tube containing the washed
precipitates. The solutions were thoroughly mixed before being subjected to centrifugation
Student’s name:
Panther ID:
CHM1045L
TA name:
Purpose:
This experiment explores how silver, lead (II), nickel, barium, and iron (III) ions interact with
different reagents and observes reactions, including the formation of precipitates and color
changes, ions can be identified. Furthermore, the experiment seeks to develop a flowchart
that outlines the confirmatory tests for analyzing unknown samples containing these cations
and provides a structured approach to identifying the ions present in unknown samples.
Procedure:
The experiment commenced with the washing and labeling of five test tubes for each ion
under investigation: silver, lead (II), nickel, barium, and iron (III). Following this, a sequence
of chemical tests was initiated on each test solution, starting with the addition of sulfate using
dropper bottles to dispense precisely 20 drops of the test solutions into their respective
labeled test tubes. Subsequently, 10 drops of 3 M H2SO4 were added to each test tube, and
observations were recorded for any resulting precipitates or color changes in Data Table 1.
Upon the formation of precipitates, the samples were carefully mixed with a clean stirring rod
and subjected to centrifugation. Once the observations were recorded, both the solutions and
precipitated were discarded.
, For the addition of HCl, 20 drops of the test solution were added to each labeled test tube,
followed by the addition of 10 drops of 6 M HCl. Upon the formation of the precipitate, the
samples were mixed with a clean stirring rod and subjected to centrifugation. Following
centrifugation, the supernatant was discarded, and the precipitant was washed twice with 1
mL of deionized water each time, ensuring the removal of any remaining supernatant.
The next steps involved the heating of precipitates and the addition of K2CrO4. The
precipitate formed in Test 2 was treated and 4mL of deionized water to the test tubes was
added, ensuring thorough mixing of the solutions. The test tubes with precipitate were placed
in a hot water bath for 5 minutes, with frequent stirring to ensure proper dissolution. The test
tubes were then subjected to centrifugation and the supernatant from each sample was poured
into a clean test tube. Subsequently, 2 drops of K2CrO4 were added to the hot liquid, and
observations were recorded in Data Table 1 followed by the remaining supernatants being
discarded.
For the addition of NaOH, 20 drops of the test solutions were added to clean test tubes
followed by the addition of 4 drops of 6 M NaOH. In the event of precipitate formation, the
sample was mixed, and centrifugation was performed. Observations were recorded in Data
Table 5. Upon completion of centrifugation, the supernatant was discarded and the precipitate
was washed twice with deionized water.
Finally, 20 drops of 15 M NH3 were added to each test tube containing the washed
precipitates. The solutions were thoroughly mixed before being subjected to centrifugation
