A solution contains three cations, Ba$^{2+}$, Cu$^{2+}$ and Pb$^{2+}$ - HSC - SSCE Chemistry - Question 22 - 2013 - Paper 1
Question 22
A solution contains three cations, Ba$^{2+}$, Cu$^{2+}$ and Pb$^{2+}$. The flow chart indicates the plan used to confirm the identity of these cations.
Solution con... show full transcript
Worked Solution & Example Answer:A solution contains three cations, Ba$^{2+}$, Cu$^{2+}$ and Pb$^{2+}$ - HSC - SSCE Chemistry - Question 22 - 2013 - Paper 1
Step 1
Name Precipitate 2.
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Answer
Precipitate 2 is Barium Sulfate (BaSO4).
Step 2
Write a balanced net ionic equation for the formation of Precipitate 1.
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Answer
The balanced net ionic equation for the formation of Precipitate 1, which is Lead(II) Chloride (PbCl2), is:
Pb2+(aq)+2Cl−(aq)→PbCl2(s)
Step 3
Suggest a test and the expected result that would confirm the identity of the metal cation remaining in Filtrate 2.
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A suitable test for confirming the identity of the metal cation in Filtrate 2 is to add a few drops of sodium hydroxide (NaOH) solution, which will cause the formation of a blue precipitate if Copper(II) ions (Cu2+) are present.
Expected Result: A blue precipitate indicates the presence of Copper(II) ions.
