Use of halogen acids

Use of halogen acids Halogen acids can be used in three different forms

(1) Hydrofluoric Acid

(2)Hydrochloric Acid

(3) Hydrobromic Acid

(4) Hydroiodic Acid

(1) Hydrofluoric acid is used:-

a) In the manufacture of fluorine.

b) For removing silica from artificial graphite and other castings.

c) As an antiseptic in brewing industries.

d) For making fluorides. NaF is used as an insecticide. AIF₃ is used in the extraction of aluminium. Fluorides of alkali metals and antimony are used as mordants in dyeing industry. UF₆ is used for separation of U²³⁵ and U²³⁸ isotopes by diffusion method.

e) For etching glass, the glass surface to be etched is coated with paraffin wax, the design is scratched on glass through a knife on wax coating. The scratched portion is exposed to HF solution for few hours and marked accordingly. Now the wax is completely scratched off and glass surface is properly marked.

(2) Hydrochloric Acid:-

a) As a laboratory reagent.

b) For cleaning iron sheets during tin plating, soldering and galvanization.

c) In medicines.

d) In the preparation of chlorine, chlorides and aqua-regia.

e) For extraction of glue from animal tissues and bones.

(3) Hydrobromic Acid

a) As a laboratory reagent for preparing bromo derivatives of unsaturated organic compounds.

b) For making NaBr and KBr which are used as sedatives.

c) For making AgBr used in photography.

4) Hydroiodic Acid

a) As a reducing agent in organic chemistry.

b) For making KI which is used in medicines.

c) For making AgI which is used in photography.