What Is Alcohol?
In general usage, alcohol refers almost always to ethanol, also known as grain alcohol, and often to any beverage that contains ethanol (see alcoholic beverage). This sense underlies the term alcoholism (addiction to alcohol). Other forms of alcohol are usually described with a clarifying adjective, as in isopropyl alcohol or by the suffix -ol, as in isopropanol.
As a drug, common alcohol (ethanol) is known to have a depressing effect that decreases the responses of the central nervous system.
In chemistry, alcohol is a more general term, applied to any organic compound in which a hydroxyl group (-OH) is bound to a carbon atom, which in turn is bound to other hydrogen and/or carbon atoms. The general formula for a simple acyclic alcohol is CnH2n+1OH.
Alcohol Structure
The functional group of an alcohol is a hydroxyl group bonded to an spł hybridized carbon. It can therefore be regarded as a derivative of water, with an alkyl group replacing one of the hydrogens. If an aryl group is present rather than an alkyl, the compound is generally called a phenol rather than an alcohol. Also, if the hydroxyl group is bonded to one of the sp˛ hybridized carbons of an alkenyl group, the compound is referred to as an enol. The oxygen in an alcohol has a bond angle of around 109° (c.f. 104.5° in water), and two nonbonded electron pairs. The O-H bond in methanol (CH3OH) is around 96 picometres long.
Uses of Alcohol
Alcohols are in wide use in industry and science as reagents, solvents, and fuels. Ethanol and methanol can be made to burn more cleanly than gasoline or diesel. Because of its low toxicity and ability to dissolve non-polar substances, ethanol is often used as a solvent in medical drugs, perfumes, and vegetable essences such as vanilla. In organic synthesis, alcohols frequently serve as versatile intermediates.
Ethanol is also commonly used in beverages after fermentation to promote flavor or induce a euphoric intoxication commonly known as "drunkenness" or "being drunk". The use of ethanol for this purpose is illegal in some jurisdictions. In such instances of consumption, alcohol is not only a drug, with immediate potential for overdose, toxic poisoning, and physiological dependency (known as alcoholism). Alcoholism has become one of the most common drug addictions (if not second to caffeine) in the world. The physiological dependency caused by alcoholism means that the user experiences physical withdrawal (in the form of a headache known as a "hangover," extremely high anxiety known as "the shakes," and restlessness or trouble sleeping) upon cessation or decrease of use. For the full article on this topic see effects of alcohol on the body.
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