Why is calcium oxide capable of neutralizing acids?

Answer 1

When CaO (lime) is in contact with water (moist soil), the ionic bond breaks -- it dissolves into Ca2+ and O2- ions. It is the O2- ions that will neutralize acids, which are characterized by providing H+ (or H3O+) ions. The chemical reaction is: 2H+ + O2---> H2O, which plants need and which is neutral. Ca2+will probably remain as ions, because the salts form in the chemical reaction (for example, CaSO4, CaCl2, or Ca(NO3)2) are still water soluble.

OK, then why not MgO or Al2O3? Beside that CaO is relative common and therefore cheap to mine (limestone is almost everywhere), it provides as a bonus, Ca, a mineral that the plant needs anyway. Al2O3 is out of the question, because it is insoluble in water to be any good. CaCO3, another abundant substance, is OK too, but that CO2 is a byproduct.

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Answer 2

According to the Bronsted-Lowry definition of acids and bases: an acid is a proton donor and a base is a Proton Acceptor.

I believe calcium oxide readily accepts protons from the solution.

It is known to hydrate quite easily to Ca(OH)2 which is a powerful base for acid neutralization due to the strong donation of -OH (hydroxide ions) to the solution.

Answer 3

Calcium oxide reacts with water to form calcium hydroxide, which is a strong base. Calcium hydroxide has the ability to neutralize acids by reacting with the hydrogen ions present in the acid to form water. This reaction helps to balance the pH level by decreasing the acidity.

Answer 4

Calcium oxide is added to reduce the acidity of the soil

Answer 5

Calcium carbonate is more basic than calcium oxide. So it will be better choice.

Answer 6

calcium carbonate