Metal carbonates such as calcium carbonate (chalk) react with acids to produce the gas carbon dioxide. This can be seen in the equation:
Metal carbonate + Acid Salt + Water + Carbon dioxide
The carbon dioxide produced can be tested for in the lab using limewater, which reacts with the carbon dioxide gas. When the limewater reacts with carbon dioxide gas it turns from colourless to milky white in colour.
NB: bear in mind that the limewater isn't actually blue! It's colourless.
The salt produced depends on the acid that's used to produce it. The table below shows the type of salts that are produced from these acids:
|Acid Name||Type of Salt|
The name of the salts produced is better illustrated in an equation:
Magnesium carbonate + Hydrochloric acid Magnesium chloride + Water + Carbon dioxide
MgCO3+ 2HClMgCl2 + H2O + CO2
Calcium carbonate + Sulfuric acid Calcium sulfate + Water + Carbon dioxide
CaCO3+ H2SO4CaSO4 + H2O + CO2
Sodium carbonate + Sulfuric acid Sodium nitrate + Water + Carbon dioxide
Na2CO3+ 2HNO32NaNO3 + H2O + CO2