Test for Carbonates

  • Carbonates all contain the carbonate ion, CO32-.
  • The test for this ion involves adding dilute acid and testing the gas released.
  • If a carbonate compound is present then effervescence should be seen and the gas produced is CO2 which forms a white precipitate of calcium carbonate when bubbled through limewater:

CO32-(aq) + 2H+(aq) → CO2(g) + H2O(l)

CO2+ Ca(OH)2 → CaCO3(s) + H2O(l)

Test for Carbon Dioxide, IGCSE & GCSE Chemistry revision notes

Limewater turns milky in the presence of CO2 caused by formation of insoluble calcium carbonate

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Morgan Curtin Chemistry

Author: Morgan

Morgan’s passion for the Periodic Table begun on his 10th birthday when he received his first Chemistry set. After studying the subject at university he went on to become a fully fledged Chemistry teacher, and now works in an international school in Madrid! In his spare time he helps create our fantastic resources to help you ace your exams.