formation of basic oxides?

Answer 1

very comprehensive @:
http://en.wikipedia.org/wiki/Basic_oxide

Answer 2

An oxide is a chemical compound containing an oxygen atom, together with other chemical elements. Most of the earth's crust consists of oxides. Oxides result when elements are oxidized by air. Combustion of hydrocarbons affords the two principal oxides of carbon, carbon monoxide and carbon dioxide. Even materials that are considered to be pure elements often contain a coating of oxides. For example, aluminium foil has a thin skin of Al2O3 that protects the foil from further corrosion

The oxide anion, O2−, is the conjugate base of the hydroxide ion, OH−, and is encountered in ionic solid such as calcium oxide. O2− is unstable in aqueous solution − its affinity for H+ is so great that it abstracts a proton from a solvent H2O molecule:

O2− + H2O → 2 OH−
Although many anions are stable in aqueous solution, ionic oxides are not. For example, sodium chloride dissolve readily in water to give a solution containing the constitutent ions, Na+ and Cl-. Oxides does not behave like this. When an ionic oxide dissolves, the O2− ions become protonated. Although Calcium oxide, CaO, is said to "dissolve" in water, the products includehydroxide:

CaO + H2O → Ca2+ + 2 OH-
In fact, no monoatomic dianion is known to dissolve in water - all are so basic that they undergo hydrolysis.

Authentic soluble oxides do exist of course, but they release oxyanions, not O2-. Well known soluble salts of oxyanions include sodium sulfate (Na2SO4), potassium permanganate (KMnO4), and sodium nitrate (NaNO3).

Answer 3

you have to have a number of ionizible hydrogen atoms in an acid, being equal to the number of equivalents of a base that will react with one mole of the compound.