An aqueous solution is a solution in which the solvent is water. It is usually shown in chemical equations by appending (aq) to the relevant formula. For example, a solution of ordinary table salt, or sodium chloride (NaCl), in water would be represented as NaCl(aq). The word aqueous means pertaining to, related to, similar to, or dissolved in water. As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry.
Substances which are hydrophobic ('water fearing') often do not dissolve well in water whereas those that are hydrophilic ('water-loving') do. An example of a hydrophilic substance is sodium chloride. Acids and bases are aqueous solutions, as part of their Arrhenius definitions.
Aqua fortis, or "fortified water," in alchemy, is nitric acid (HNO3). Being highly corrosive, the solution was used in alchemy for dissolving silver and most other metals with the notable exception of gold, which can only be dissolved using aqua regia or "regal water". Aqua fortis was prepared by mixing either sand, alum, or vitriol, or the last two together, with saltpeter, then distilling it by a hot fire. The gas collected from this condenses into aqua fortis. It was first described by alchemist Pseudo-Geber.
Aqua fortis was useful to refiners for parting or separating silver from gold and copper; to the workers in mosaic for staining and coloring their woods; to other artists for coloring of bone and ivory, which is done by tinging the items with copper or verdigris, then soaking in aqua fortis. Some also turn it into aqua regia, by dissolving in a quarter of its weight of sal ammoniac, and then use this to stain ivory and bone, of a fine purple color. Book binders also put it on leather, making fine marble covers for books. Diamond cutters used it to separate diamonds from metalline powders. It was also used in etching copper or brass plates. It was mixed with oil of vitriol and used to stain canes to appear like a tortoise shell by applying several coats while the cane is over hot coals. The canes were then given a gloss with a little soft wax and a dry cloth.
A mineral acid (or inorganic acid) is an acid derived from one or more inorganic compounds, and all mineral acids form hydrogen ions and the conjugate base ions when dissolved in water.
Commonly used mineral acids are sulfuric acid, hydrochloric acid and nitric acid (They are also known as bench acids). Mineral acids range from acids of great strength (example: sulfuric acid) to very weak (boric acid). Mineral acids tend to be very soluble in water and insoluble in organic solvents.