Core Reactions: Acid-base
Slide 23 of 42
Characteristic reactions of acids continued
IV. Reactions with solid carbonates, hydrogencarbonates, sulfites, hydrogen sulfites—reaction where a weak acid is produced.
-In this type of reactions, the weak acid products either are unstable and dissociate into a gas and water (as in the case of carbonates, hydrogen carbonates, sulfites and hydrogensulfites) or is liberated as gas (as in the case of sulfides).
–General forms of molecular equations for reactions with carbonates and hydrogen carbonates:
– Metal carbonate (s or aq) + Acid (aq) ® Salt (aq) + H2CO3 (aq)   
– But, carbonic acid is unstable and will dissociates spontaneously.
– H2CO3 (aq) ® CO2 (g) + H2O (l) 
– \ Metal carbonate (s or aq) + Acid (aq) ® Salt (aq) + CO2 (g) + H2O (l)
–Similarly,
– Metal hydrogencarbonate (s) + Acid (aq) ® Salt (aq) + H2CO3 (aq)   
– But, H2CO3 (aq) ® CO2 (g) + H2O (l)
– \ Metal hydrogencarbonate (s or aq) + Acid (aq) ® Salt (aq) + CO2 (g) + H2O (l)