Hydrochloric acid 12%, consisting of fuming hydrochloric acid and distilled water, is widely used in metallography and scientific laboratories. It is an integral part of the BERAHA II color etchant kit, known for its metal contrasting ability.

Its chemical formula HCl characterizes it as a strong acid that dissociates in water to form hydronium and chloride ions. This dissociation gives hydrochloric acid its characteristic acidic properties and the ability to act as a proton donor, enabling a range of chemical reactions.

Within the BERAHA II color etchant kit, hydrochloric acid 12% is used to create strong acid conditions that enable a selective etching reaction on metallic surfaces. This reaction results in the highlighting of specific microstructural features, allowing detailed examination and analysis of metallic samples.