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Four students were asked to test a solution for the presence of a cation by using various anions - HSC - SSCE Chemistry - Question 15 - 2001 - Paper 1
Question 15
Four students were asked to test a solution for the presence of a cation by using various anions. The students obtained these results: Student Chloride Sulfate C... show full transcript
Worked Solution & Example Answer:Four students were asked to test a solution for the presence of a cation by using various anions - HSC - SSCE Chemistry - Question 15 - 2001 - Paper 1
Step 1
Which student had results consistent with this conclusion?
Answer
To determine which student's results are consistent with the conclusion that Pb^2+ was present, we need to analyze the table of results:
- Lead (II) Chloride (PbCl2) forms a precipitate with chloride ions. Hence, a positive test would show a precipitate in the Chloride column.
- Lead (II) Sulfate (PbSO4) forms a precipitate with sulfate ions. Thus, a positive test would indicate a precipitate in the Sulfate column.
- Lead (II) Carbonate (PbCO3) also forms a precipitate. A positive test would show precipitation in the Carbonate column.
Now, let's evaluate each student's results:
- Student A: no precipitate in Chloride, no precipitate in Sulfate, precipitate in Carbonate (not consistent).
- Student B: precipitate in Chloride, no precipitate in Sulfate, no precipitate in Carbonate (not consistent).
- Student C: precipitate in Chloride, precipitate in Sulfate, precipitate in Carbonate (consistent).
- Student D: no precipitate in Chloride, precipitate in Sulfate, no precipitate in Carbonate (not consistent).
Based on this analysis, the only student whose results consistently indicate the presence of Pb^2+ is Student C.