- published: 26 Jan 2010
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Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and a hydrogen atom held together by a covalent bond, and carrying a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, as a ligand, a nucleophile, and a catalyst . The hydroxide ion form salts, which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. A hydroxide group attached to a strongly electropositive center may itself dissociate, liberating a hydrogen cation (H+), making the parent compound an acid.
In organic chemistry, the hydroxide ion can act as a catalyst or as a nucleophilic reagent. An OH group, known as an hydroxyl group, is present in alcohols, phenols, carboxylic acids and related functional groups.
The hydroxide ion is a natural constituent of water, because of the self-ionization reaction:
The equilibrium constant for this reaction, defined as
has a value close to 10−14 at 25 °C, so the concentration of hydroxide ions in pure water is close to 10−7 mol dm−3, in order to satisfy the equal charge constraint. The pH of a solution is equal to the decimal cologarithm of the hydrogen cation concentration; the pH of pure water is close to 7 at ambient temperatures. The concentration of hydroxide ions can be expressed in terms of pOH, which is close to 14 – pH, so pOH of pure water is also close to 7. Addition of a base to water will reduce the hydrogen cation concentration and therefore increase the hydroxide ion concentration (increase pH, decrease pOH) even if the base does not itself contain hydroxide. For example, ammonia solutions have a pH greater than 7 due to the reaction NH3 + H+ NH4+, which results in a decrease in hydrogen cation concentration and an increase in hydroxide ion concentration. pOH can be kept at a nearly constant value with various buffer solutions.
Donald John Trump, Sr. (born June 14, 1946) is an American business magnate, television personality and author. He is the chairman and president of The Trump Organization and the founder of Trump Entertainment Resorts. Trump's extravagant lifestyle, outspoken manner and role on the NBC reality show The Apprentice have made him a well-known celebrity who was No. 17 on the 2011 Forbes Celebrity 100 list. He is well-known as a real-estate developer who amassed vast hotel, casino, and other real-estate properties, in the New York City area and around the world.
Trump is the son of Fred Trump, a wealthy New York City real-estate developer. He worked for his father's firm, Elizabeth Trump & Son, while attending the Wharton School of the University of Pennsylvania, and in 1968 officially joined the company. He was given control of the company in 1971 and renamed it The Trump Organization.
In 2010, Trump expressed an interest in becoming a candidate for President of the United States in the 2012 election. In May 2011, he announced he would not be a candidate, but a few weeks later he said he had not completely ruled out the possibility. In December 2011, Trump was suggested as a possible Vice Presidential selection by Michele Bachmann. Bachmann has since suspended her presidential campaign.