Testing For Carbonate Ions

Question 1

What test would you carry out to test for the presence of carbonate ions ?

Answer 1

• a small amount of dilute HCl should be added to a test tube using a pipette
• an equal amount of sodium carbonate solution should then be added to the test tube using a clean pipette
• as soon as the sodium carbonate is added a bung with a delivery tube should be attracted to the test tube
• the delivery tube should transfer the gas which is formed into a different test tube which contains a small amount of limewater

Question 2

What would you observe if carbonate ions are present ?

Answer 2

Carbonate ions will react with hydrogen ions from the acid to produce carbon dioxide gas

Carbon dioxide gas will turn the lime water milky