Hydrazoic acid was originally prepared by the reaction of aqueous hydrazine with nitrous acid. Other oxidizing agents, such as hydrogen peroxide, nitrosyl chloride, trichloramine or nitric acid, can also be used. In its properties hydrazoic acid shows some analogy to the halogen acids, since it forms poorly soluble (in water) lead, silver and mercury(I) salts. The metallic salts all crystallize in the anhydrous form and decompose on heating, leaving a residue of the pure metal. It is a weak acid (p"K" = 4.75.) Its heavy metal salts are explosive and readily interact with the alkyl iodides. Azides of heavier alkali metals (excluding
Acid–base reaction these examples. For instance, carbon monoxide acts as a Lewis base when it forms an adduct with boron trifluoride, of formula FB←CO. Adducts involving metal ions are referred to as co-ordination compounds; each ligand donates a pair of electrons to the metal ion. The reaction can be seen as an acid–base reaction in which a stronger base (ammonia) replaces a weaker one (water) The Lewis and Brønsted–Lowry definitions are consistent with each other since the reaction is an acid–base reaction in both theories. One of the limitations of the Arrhenius definition is its reliance on water solutions. Edward Curtis Franklin