Qualitative Analysis Laboratory: Identifying Metal Ions in Solutions with Chemical Tests

Test Observations and Results:

1. Copper (Cu2+) Test:
   • Procedure: 3ml of copper solution mixed with concentrated ammonium hydroxide until the solution becomes basic (confirmed with litmus paper).
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   • Observation: Presence of a blue color indicates the presence of copper ions.
2. Silver (Ag1+) & Lead (Pb2+) Test:
   • Procedure: 3ml of silver and lead solution with 2-3 drops of 6M HCL.
   • Observation: Formation of a white precipitate; upon heating, lead dissolves while silver ions do not.
3. Nickel (Ni) Test:
   • Procedure: 3ml of nickel solution with 6ml NH4OH for basification and 3 drops of dimethylglyoxime.
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   • Observation: Presence of a red precipitate indicates the presence of nickel ions.
4. Aluminum (Al) Test:
   • Procedure: 3ml of aluminum solution with either 6M NH4OH or 6M HCL to achieve a pH around 6. A drop of the solution is placed on filter paper, and one drop of aluminum solution is added, followed by rinsing the filter paper with distilled water.
   • Observation: The presence of a red spot on the filter paper indicates the presence of aluminum ions.

Unknown Sample No: 12

• The copper solution contains copper ions that react with ammonium hydroxide in a basic environment, resulting in a blue color.
• The silver and lead solution reacts with hydrochloric acid, forming silver chloride and lead chloride, indicating the presence of Ag+ or Pb+ ions. After heating, only lead chloride dissolves.
• The nickel solution reacts with dimethylglyoxime in the presence of ammonium hydroxide to basify, producing a red precipitate.
• For the aluminum solution, adjusting the pH to 6 and placing a drop on filter paper results in the formation of a red spot after 30 seconds, indicating the presence of aluminum ions.

Conclusion:

• The qualitative analysis test of the given solution was conducted as per the procedure, and it was determined that the unknown sample (No: 12) contained copper ions (Cu2+).

Safety Precautions:

• Handle NaOH with care as it can cause skin irritation.
• Wear goggles and an apron in the lab.
• Wash hands after leaving the lab.

Answers:

1. Group IA has a predicted ionic charge of metal ions with a positive charge of +1 (e.g., H+1, Na+1). Group IIA has a predicted ionic charge of metal ions with a positive charge of +2 (e.g., Ca+2, Mg+2). Group IIIA has a predicted ionic charge of metal ions with a positive charge of +3 (e.g., B+3, Al+3).
2. a) Potassium: Loses one electron, forming K+1. b) Sulphur: Gains two electrons, forming S-2. c) Fluorine: Gains one electron, forming F-1. d) Barium: Loses two electrons, forming Ba+2. e) Copper: Loses two electrons, forming Cu+2.
3. Avogadro's number is 6.02 * 10^23. The years to spend money is 523 * 10^5.

In this qualitative analysis laboratory, we aim to identify the presence of specific ions in given solutions through a series of chemical tests. The ions under investigation include copper (Cu2+), silver (Ag1+), lead (Pb2+), nickel (Ni), and aluminum (Al). The experimental procedures involve various reagents and reactions tailored to each ion.

Experiment 1: Copper (Cu2+) Determination Test

Procedure:

1. Combine 3ml of copper solution with concentrated ammonium hydroxide until the solution turns basic.
2. Confirm the basic nature with litmus paper.

Observation: The formation of a blue color indicates the presence of copper ions.

Calculation/Formulas: No specific calculations are required for this qualitative test.

Results: The presence of copper ions is confirmed by the blue coloration.

Experiment 2: Silver (Ag1+) & Lead (Pb2+) Determination Test

Procedure:

1. Mix 3ml of silver and lead solution with 2-3 drops of 6M HCL.
2. Observe the formation of a white precipitate.
3. Heat the solution; lead chloride dissolves while silver chloride does not.

Observation: Formation of a white precipitate indicates the presence of silver and lead ions. The differential solubility upon heating distinguishes between the two.

Calculation/Formulas: No specific calculations are involved; the observations are qualitative.

Results: The presence of silver and lead ions is confirmed by the formation of a white precipitate.

Experiment 3: Nickel (Ni) Determination Test

Procedure:

1. Combine 3ml of nickel solution with 6ml NH4OH for basification.
2. Add 3 drops of dimethylglyoxime.

Observation: The appearance of a red precipitate indicates the presence of nickel ions.

Calculation/Formulas: No specific calculations are required for this qualitative test.

Results: The presence of nickel ions is confirmed by the formation of a red precipitate.

Experiment 4: Aluminum (Al) Determination Test

Procedure:

1. Take 3ml of aluminum solution and adjust the pH to 6 using 6M NH4OH or 6M HCL.
2. Place a drop of the solution on filter paper and observe the formation of a red spot after 30 seconds.

Observation: The presence of a red spot on the filter paper indicates the presence of aluminum ions.

Calculation/Formulas: No specific calculations are involved in this qualitative test.

Results: The presence of aluminum ions is confirmed by the formation of a red spot on the filter paper.

Conclusion

The qualitative analysis tests conducted as per the outlined procedures have successfully identified the presence of specific ions in the given solutions. The results confirm the presence of copper, silver, lead, nickel, and aluminum ions through distinctive reactions and observations.

Safety Precautions

1. Handle NaOH with care to avoid skin irritation.
2. Always wear goggles and an apron in the laboratory.
3. Wash hands thoroughly after leaving the lab.

Answers to Questions

Answer 1: Group I, II, III Predicted Ionic Charges

• Group I (A): Predicted ionic charge of metal ions is +1 (e.g., H+1, Na+1).
• Group II (B): Predicted ionic charge of metal ions is +2 (e.g., Ca+2, Mg+2).
• Group III (C): Predicted ionic charge of metal ions is +3 (e.g., B+3, Al+3).

Answer 2: Predicted Ionic Charges for Specific Elements

• Potassium: Loses one electron, forming K+1.
• Sulphur: Gains two electrons, forming S-2.
• Fluorine: Gains one electron, forming F-1.
• Barium: Loses two electrons, forming Ba+2.
• Copper: Loses two electrons, forming Cu+2.

Answer 3: Avogadro's Number and Years to Spend Money

• Avogadro's number: 6.02 * 10^23.
• Years to spend money: 523 * 10^5.

This qualitative analysis laboratory not only serves as a practical application of chemical principles but also emphasizes the importance of safety precautions in laboratory settings. The incorporation of specific experiments, calculations, and safety measures ensures a comprehensive and educational experience for students in the field of qualitative analysis.