question archive The reactions between an acid and a metal carbonate or a metal hydrogen carbonate are double displacement reactions that produce carbonic acid
The reactions between an acid and a metal carbonate or a metal hydrogen carbonate are double displacement reactions that produce carbonic acid
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The reactions between an acid and a metal carbonate or a metal hydrogen carbonate are double displacement reactions that produce carbonic acid.
In a double displacement reaction, the cations change partners:
A?B? + C?D? → A?D? + C?B?
To form H?CO? as a product, the equation must be of the form:
2H?B? + (C?)?CO?²? → H?CO? + 2C?B?
or
H?B? + C?HCO?? → H?CO? + C?B?
Typical examples are
2HCl + Na?CO? → H?CO? + 2NaCl
H?SO? + CaCO? → H?CO? + CaSO?
HCl + NaHCO? → H?CO? + NaCl
H?SO? + Ca(HCO?)? → H?CO? + CaSO?
The carbonic acid is unstable. It rapidly decomposes into water and carbon dioxide.
H?CO? → H?O + CO?
Many baking powders are of a weak acid and a hydrogen carbonate salt such as NaHCO?. They work by forming carbonic acid in a double displacement reaction. The bubbles of carbon dioxide expand in the moist batter and leaven the mixture.
