Hydrobromic acid

Hydrobromic

Colorless, fuming liquid at high concentrations

Liquid

1.48 g · cm -3 ( 47.63 %)

126 ° C ( 47.63 % azeotrope )

Risk

Template: Infobox chemical / molecular formula search is not possible

Hydrobromic denotes the solutions of gaseous hydrogen bromide ( HBr) in water. The solutions react, as the other hydrogen halides, strongly acidic.

In the chemical symbol language is meant by HBr both the gas as well as its aqueous solution. Where a distinction or a more accurate identification of the aqueous solution is required, can be found using the abbreviation aq names such as HBr (aq ), HBr aq, aq HBr or HBraq.

Properties

Hydrobromic acid behaves very similar to the chemically related hydrochloric acid. Just as the gaseous hydrogen chloride HCl to the colorless gas HBr dissolves easily in water, the solvent power decreases at standard pressure of HBr with increasing temperature of the water until it corresponds to the composition of the azeotrope described below.

At room temperature is obtained as an aqueous solution with a maximum of 65 percent HBr (mass fraction ) and a density of 1.7675 g/cm3. Commercially are solutions with 40-65 %. HBr and water form (as HCl ) is a positive azeotrope at 47.63 % HBr and 52.37 % H2O, which boils at 126 ° C; the density of this solution is 1.482 g/cm3. By simple distillation, this ratio can not change the azeotropic point, as the liquid and the gas phase have the same composition.

Since hydrobromic acid is a very strong acid, HBr molecule is in aqueous solution before almost completely dissociated, it is Br - split in the H cation and the anion:

Since H ions do not exist isolated in aqueous solution, but to store together with water molecules, to write these often nearly as H3O . Taking this into account, one arrives for the solution of HBr in water to the equation.

The H3O ion is also referred to as oxonium ion ( former names: hydroxonium or hydronium ion ).

As well as hydrochloric acid, hydrobromic acid dissolves most metals and metal oxides with the formation of bromides. Hydrobromic acid and its vapors are highly corrosive. Even stainless steel forms within 24 hours of " rust " when it is in contact with HBr vapors. As opposed to the meaning of the hydrobromic acid is small, it is hardly used in the chemical industry.