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 chemistry. The ECW model is quantitative model that describes and predicts the strength of Lewis acid base interactions, −Δ"H". The model assigned "E" and "C" parameters to many Lewis acids and bases. Each acid is characterized by an "E" and a "C". Each base is likewise characterized by its own "E" and "C". The "E" and "C" parameters refer, respectively, to the electrostatic and covalent contributions to the strength of the bonds that the acid and base will form. The equation is The "W" term represents a constant energy contribution for acid–base reaction such as the cleavage of a dimeric