How does limestone neutralise soil?

Answer 1

Limestone, aka calcium carbonate (CaCO3) reacts with acid to forma calcium salt, water and carbon dioxide.

This is how it can remove acid in soil.

CaCO3 (s) + 2H+ (aq) --> Ca2+ (aq) + H2O (l) + CO2 (g)

Answer 2

Limestone, which is predominantly Calcium Carbonate or CaCO3, is the salt of the weak acid H2CO3. H2CO3 is also known as carbonic acid and is the result of carbon dioxide being dissolved in water. A salt is the reaction product of an acid which trades its hydrogen atom for a metal, usually an alkali (Li group) or alkaline earth (Be group). Salts of weak acids are weak bases, and when CaCO3 comes into contact with acidic soil, the reaction reverses. The carbonic acid is reformed, which allows the carbon dioxide to be released as a gas leaving the pH of the soil more neutral and dissolving calcium in the moisture of the soil.

H2O + CO2 ==> H+ + HCO3- (Carbon dioxide dissolves in water to form carbonic acid)

H+ + HCO3- + Ca++ + 2OH- ==> 2H2O + CaCO3 (Dissolved calcium with carbonic acid forms solid lime)

CaCO3 + 2H+ + 2NO3- ==> H2O + CO2 + Ca++ + 2NO3- (Lime reacts with nitric acid to form gaseous carbon dioxide and dissolved calcium nitrate)

Answer 3

Limestone is lime... probably. Generally, "lime" by itself refers to crushed limestone (calcium carbonate), as opposed to "quicklime" (calcium oxide) or "slaked lime" (calcium hydroxide).

Answer 4

Limestone is basically calcium carbonate, and reacts with acids to form calcium salts plus carbon dioxide plus water. Removal of acids raises pH.