If, on the contrary, X is an atom of higher electronegativity, such as nitrogen, the electrons are shared between X and O. The electronegativity of O then weakens the O-H bond by pulling the electrons of that bond toward O.

In aqueous solution, water molecules cause the substance to dissociate in a different way:



(Both ions are hydrated, of course.) The solution is acidic because hydrogen ions are produced. As we shall see shortly, this is the behavior of nitric acid, in which the ionization is :