Escience 5: Qualitative Analysis Of Ions
pre-lab Questions
1. What is one difference between qualitative and quantitative analysis?
2. Use Table 1 to determine which metal ion would be identified as the reactant if a reaction with ammonia produces a violet complex? Use scientific reasoning to explain your answer.
3. Use the pH scale to describe an acidic solution and a basic solution. At what pH would a solution be considered neutral? Why?
experiment 1: qualitative analysis of reactions
Data Sheet
Table 2: Litmus Test Results of OH- and H+ Solution Type
Initial Litmus Color
Final Litmus Color
Acid or Base? Acetic acid
Purple
Red
Acid Sodium bicarbonate
Purple
Blue
Base Table 3: Test Results Solution Type
Indicator
Observations Initial
Final Carbonate Ion
Bubble formation when an acid is added
Clear solution
Bubbles Sulfate Ion
White precipitates when barium chloride is added to the solution.
Clear solution
White precipitates Phosphate Ion
Formation of white precipitate
Clear solution
White precipitate formed Calcium Ion
Formation of precipitate
Clear solution
Precipitate Table 4: Determination of an Unknown Results
Carbonate Ion Test Tube
Sulfate Ion Test Tube
Phosphate Ion Test Tube Observations
No bubbles observed. Solution remained clear
No precipitate
White precipitate formed Result: Positive or Negative?
Negative
Negative
positive
Post-Lab Questions
1. What ion is contained in the unknown solution? Use your results as evidence.
2. Imagine that the unknown solution contains aqueous ammonium sulfate, which is commonly used in fertilizer. Write a balanced equation for the precipitation of barium sulfate after mixing aqueous ammonium sulfate and barium chloride.
3. Identify and discuss any sources of error for this experiment. How could you mitigate error?
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