Testing for Sulfate Ions (WJEC GCSE Chemistry: Combined Science)

Revision Note

Philippa Platt

Last updated

Test for Sulfates

  • Acidify the sample with dilute hydrochloric acid and then add a few drops of aqueous barium chloride
  • If a sulfate is present then a white precipitate of barium sulfate is formed:

Ba2+ (aq) + SO42- (aq) → BaSO4 (s)

  • The test can also be carried out with barium nitrate solution

Diagram to show the test for sulfate ions

Sulfate Ion Test, IGCSE & GCSE Chemistry revision notes

A white precipitate of barium sulfate is a positive result for the presence of sulfate ions

Examiner Tip

HCl is added first to remove any carbonates which may be present and would also produce a precipitate and  interfere with the results.

This test can be carried out using nitric acid and barium nitrate. The barium ion from the nitrate will again form a white precipitate of barium sulfate.

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Philippa Platt

Author: Philippa Platt

Expertise: Chemistry

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener.