Testing Sulfates 2
Chemistry: Edexcel IGCSE, topic 13.2.10
Testing for Sulfates
Sulfates are compounds that contain SO42− ions. There are two steps to sulfate testing:
Add dilute hydrochloric acid
- Add dilute hydrochloric acid to an unknown solution.
- This removes carbonate ions. These could disrupt test results by forming a precipitate with the barium ions added in step 2.
Add barium chloride
- Add barium chloride to the same solution.
- If sulfates are present, the white precipitate barium sulfate will form:
- Ba2+(aq) + SO42−(aq) → BaSO4(s)
Test yourself on Testing Sulfates 2
Why is hydrochloric acid added to an unknown solution when you are testing for a sulfate ion?
I test for ions in an unknown solution by adding hydrochloric acid followed by barium chloride. A white precipitate is formed. What can I say about the unknown solution?
I test for ions in an unknown solution by adding nitric acid followed by silver nitrate. A cream precipitate is formed. What can I say about the unknown solution?
I test for ions in an unknown solution by adding nitric acid followed by silver nitrate. A pale yellow precipitate is formed. What can I say about the unknown solution?
I test for ions in an unknown solution by adding barium chloride. A precipitate is formed in the reaction. What can I say about the unknown solution?