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Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. In an acidic medium, blue litmus paper turns red, while in a basic or alkaline medium, red litmus paper turns blue. In short, it is a dye and ...
Fool's gold – a mineral, iron disulfide or pyrite; can form oil of vitriol on contact with water and air. Fulminating silver – principally, silver nitride, formed by dissolving silver(I) oxide in ammonia. Very explosive when dry. Fulminating gold – a number of gold based explosives which "fulminate", or detonate easily.
[1] [2] As water is an excellent solvent and is also naturally abundant, it is a ubiquitous solvent in chemistry. Since water is frequently used as the solvent in experiments, the word solution refers to an aqueous solution, unless the solvent is specified. [3] [4] A non-aqueous solution is a solution in which the solvent is a liquid, but is ...
Paper form: It is a strip of coloured paper which changes colour to red if the solution is acidic and to blue, if the solution is basic. The strip can be placed directly onto a surface of a wet substance or a few drops of the solution can be dropped onto the universal indicator using dropping equipment.
Conversely, if a 10-fold excess of the acid occurs with respect to the base, the ratio is 1:10 and the pH is pK a − 1 or pK b − 1. For optimal accuracy, the color difference between the two species should be as clear as possible, and the narrower the pH range of the color change the better.
Another possibility is the molecular autoionization reaction between two water molecules, in which one water molecule acts as an acid and another as a base. + + + The bicarbonate ion, HCO − 3, is amphoteric as it can act as either an acid or a base:
Acid Blue AS Weak Acid Blue Acid Blue 25: 62055 anthraquinone: 6408-78-2: Acid fuchsin: Acid Magenta Acid Rubin Acid Violet 19 42685 triarylmethane: 3244-88-0: Acid orange 3 Acid orange 3 10385 nitro 6373-74-6: Acid orange 19: Acid Orange 19 14690 azo: 3058-98-8: Acid orange 20: Orange I Acid Orange 20 14600 azo 523-44-4: Acid Red 13: Fast red ...
The reaction with hydrochloric acid is an equilibrium reaction that favors formation of tetrachloroaurate(III) anions. This results in a removal of gold ions from solution and allows further oxidation of gold to take place. The gold dissolves to become chloroauric acid. In addition, gold may be dissolved by the chlorine present in aqua regia.