|
Picramic Acid
Picramic acid, also known as 2-amino-4,6-dinitrophenol, is an acid obtained by neutralizing an alcoholic solution of picric acid with ammonium hydroxide. Hydrogen sulfide is then added to the resulting solution, which turns red, yielding sulfur and red crystals. These are the ammonium salts of picramic acid, from which it can be extracted using acetic acid. Picramic acid is explosive and very toxic. It has a bitter taste. Along with its sodium salt (sodium picramate) it is used in low concentrations in certain hair dyes, such as henna Henna is a dye prepared from the plant ''Lawsonia inermis'', also known as the henna tree, the mignonette tree, and the Egyptian privet, the sole species of the genus ''Lawsonia''. ''Henna'' can also refer to the temporary body art resulting fr ..., it is considered safe for this use provided its concentration remains low. References {{reflist Acids Explosive chemicals Dinitrophenols Anilines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid
In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction. In 1983, Andreas Reuter and Theo Härder coined the acronym ''ACID'', building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems. According to Gray and Reuter, the IBM Informa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Picric Acid
Picric acid is an organic compound with the formula (O2N)3C6H2OH. Its IUPAC name is 2,4,6-trinitrophenol (TNP). The name "picric" comes from el, πικρός (''pikros''), meaning "bitter", due to its bitter taste. It is one of the most acidic phenols. Like other strongly nitrated organic compounds, picric acid is an explosive, which is its primary use. It has also been used as medicine (antiseptic, burn treatments) and as a dye. History Picric acid was probably first mentioned in the alchemical writings of Johann Rudolf Glauber. Initially, it was made by nitrating substances such as animal horn, silk, indigo, and natural resin, the synthesis from indigo first being performed by Peter Woulfe during 1771. The German chemist Justus von Liebig had named picric acid (rendered in French as ). Picric acid was given that name by the French chemist Jean-Baptiste Dumas in 1841. Its synthesis from phenol, and the correct determination of its formula, were accomplished during 1841. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Hydroxide
Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests an alkali with chemical formula, composition , it is actually impossible to isolate samples of NH4OH. The ions and OH− do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions. Basicity of ammonia in water In aqueous solution, ammonia deprotonation, deprotonates a small fraction of the water to give ammonium and hydroxide according to the following chemical equilibrium, equilibrium: : NH3 + H2O NH4+ + OH−. In a 1 Molar concentration, M ammonia solution, about 0.42% of the ammonia is converted to ammonium, equivalent to pH = 11.63 because [NH4+] = 0.0042 M, [OH−] = 0.0042 M, [NH3] = 0.9958 M, and pH = 14 + log10[OH ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
