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 Instead of defining acid–base reactions in terms of protons or other bonded substances, the Lewis definition defines a base (referred to as a "Lewis base") to be a compound that can donate an "electron pair", and an acid (a "Lewis acid") to be a compound that can receive this electron pair. For example, boron trifluoride, BF is a typical Lewis acid. It can accept a pair of electrons as it has a vacancy in its octet. The fluoride ion has a full octet and can donate a pair of electrons. Thus is a typical Lewis acid, Lewis base reaction. All