Sulfates
Chemistry: AQA GCSE Higher, topic 8.3.7
Testing for Sulfates
Sulfates are compounds that contain SO42- ions. There are 2 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 Sulfates
What are the 2 steps in sulfate testing?
Why is dilute hydrochloric acid added to a solution before testing it for sulfates with barium chloride?
Why does a white precipitate form when barium chloride is added to a solution containing sulfate ions?
Sulfate Test
Which ion must be present in a compound for it to be classed as a sulfate?