Many homeowners treat their lawns with CaCO3 (s) to reduce the acidity of the soil. Write a net ionic equation for the reaction of CaCO3 (s) With a strong acid.

The reaction of acid, assuming HCl and calcium carbonate always produces a gas. The reaction is as follows:

2 HCl + CaCO3 - - > CaCl2 + H2CO3

H2CO3, carbonic acid, is a weak acid that is unstable in water solutions at high concentrations. As such, it decomposes:

H2CO3 - - > H2O + CO2

Then,

2 HCl + CaCO3 - - > CaCl2 + H2O + CO2

The total ionic equation looks as follows:

2H + (aq) + 2 Cl - (aq) + CaCO3 (s) - - > Ca+2 (aq) + 2 Cl - (aq) + H2O (l) + CO2 (g)

Clearly, Cl - is a spectator ion as it is unchanged in the reaction. The net ionic reaction looks as follows:

2 H + (aq) + CaCO3 (s) - - > Ca+2 (aq) + H2O (l) + CO2 (g)