TEST OF PRACTICAL KNOWLEDGE QUESTION
All your burette readings (initials and final) as well as the size of your pipette must be recorded but no account of experimental procedure is required. All calculations must be done in your answer booklet.
C is a mixture of two inorganic compounds. Carry out the following exercises on C. Record your observations and identify any gas(es) evolved. State the conclusions you draw from the result of each test.
(a) Put all of C in a boiling tube and add about 10 cm\(^3\) of distilled water. Shake thoroughly and filter. Keep both the residue and the filtrate.
(b)(i) To about 2 cm\(^3\) of the filtrate add a few drops of Silver trioxoitrate (V) followed by dilute HNO\(_{3}\)
(ii) Add excess NH\(_3\) solution to the resulting mixture in (b)(i).
(C)(i) Put the residue in a test tube, add about 2 cm\(^3\) of dilute HCl and shake.
(ii) Add NH\(_3\) Solution in drops to the mixture from (c)(i) and then in excess.
Experiment:
This experiment involves analyzing a mixture (C) containing two inorganic compounds. You will perform tests on the filtrate (soluble part) and residue (insoluble part) after filtration with water.
Observations and Conclusions:
(a) Filtration:
- Observation: The mixture might separate into a clear liquid (filtrate) and a solid residue.
- Conclusion: The mixture contains at least one soluble and one insoluble compound in water.
(b) Tests on Filtrate (Solution):
(i) Silver Nitrate (AgNO3) and Nitric Acid (HNO3):
- Observation: A white precipitate might form.
- Conclusion (Possible): Presence of chloride (Cl-) ions. Silver nitrate in acidic solution reacts with chloride ions to form a white silver chloride (AgCl) precipitate.
(ii) Excess Ammonia (NH3) Solution:
- Observation: The white precipitate (if formed in step (i)) might dissolve.
- Conclusion (Possible): The white precipitate from step (i) could be AgCl. Ammonia forms a complex ion with silver ions, dissolving the AgCl precipitate.
(c) Tests on Residue:
(i) Dilute Hydrochloric Acid (HCl):
- Observation: There might be fizzing or gas evolution.
- Conclusion (Possible): Presence of a carbonate (CO3²⁻) or hydrogencarbonate (HCO3⁻) compound. These react with acid to release carbon dioxide (CO2) gas.
(ii) Ammonia Solution (NH3):
- Observation: No significant change expected.
- Conclusion: Ammonia is usually not reactive with the residue components in this type of experiment.
Important Note:
These are general observations and conclusions based on common inorganic compounds. The actual behavior depends on the specific components present in mixture C.
Experiment:
This experiment involves analyzing a mixture (C) containing two inorganic compounds. You will perform tests on the filtrate (soluble part) and residue (insoluble part) after filtration with water.
Observations and Conclusions:
(a) Filtration:
- Observation: The mixture might separate into a clear liquid (filtrate) and a solid residue.
- Conclusion: The mixture contains at least one soluble and one insoluble compound in water.
(b) Tests on Filtrate (Solution):
(i) Silver Nitrate (AgNO3) and Nitric Acid (HNO3):
- Observation: A white precipitate might form.
- Conclusion (Possible): Presence of chloride (Cl-) ions. Silver nitrate in acidic solution reacts with chloride ions to form a white silver chloride (AgCl) precipitate.
(ii) Excess Ammonia (NH3) Solution:
- Observation: The white precipitate (if formed in step (i)) might dissolve.
- Conclusion (Possible): The white precipitate from step (i) could be AgCl. Ammonia forms a complex ion with silver ions, dissolving the AgCl precipitate.
(c) Tests on Residue:
(i) Dilute Hydrochloric Acid (HCl):
- Observation: There might be fizzing or gas evolution.
- Conclusion (Possible): Presence of a carbonate (CO3²⁻) or hydrogencarbonate (HCO3⁻) compound. These react with acid to release carbon dioxide (CO2) gas.
(ii) Ammonia Solution (NH3):
- Observation: No significant change expected.
- Conclusion: Ammonia is usually not reactive with the residue components in this type of experiment.
Important Note:
These are general observations and conclusions based on common inorganic compounds. The actual behavior depends on the specific components present in mixture C.
