Chemical formula<unk>  is a 2-carbon alcohol. Its molecular formula is CH3CH2OH. An alternative notation is CH3−CH2−OH, which indicates that the carbon of a methyl group (CH3−) is attached to the carbon of a methylene group (−CH2–), which is attached to the oxygen of a hydroxyl group (−OH). It is a constitutional isomer of dimethyl ether.<unk>  is sometimes abbreviated as<unk> , using the common organic chemistry notation of representing the ethyl group (C2H5−) with Et. Physical properties<unk>  burning with its spectrum depicted<unk>  is a volatile, colorless liquid that has a slight odor. It burns with a smokeless blue flame that is not always visible in normal light. The physical properties of<unk>  stem primarily from the presence of its hydroxyl group and the shortness of its carbon chain.<unk> 's hydroxyl group is able to participate in hydrogen bonding, rendering it more viscous and less volatile than less polar organic compounds of similar molecular weight, such as propane.<unk>  is slightly more refractive than water, having a refractive index of 1.36242 (at λ=589.3 nm and ). The triple point for<unk>  is at a pressure of . Solvent properties<unk>  is a versatile solvent, miscible with water and with many organic solvents, including acetic acid, acetone, benzene, carbon tetrachloride, chloroform, diethyl ether, ethylene glycol, glycerol, nitromethane, pyridine, and toluene. Its main use as a solvent is in making tincture of iodine, cough syrups etc. It is also miscible with light aliphatic hydrocarbons, such as pentane and hexane, and with aliphatic chlorides such as trichloroethane and tetrachloroethylene.<unk> 's miscibility with water contrasts with the immiscibility of longer-chain alcohols (five or more carbon atoms), whose water miscibility decreases sharply as the number of carbons increases. The miscibility of<unk>  with alkanes is limited to alkanes up to undecane: mixtures with dodecane and higher alkanes show a miscibility gap below a certain temperature (about 13 °C for dodecane). The miscibility gap tends to get wider with higher alkanes, and the temperature for complete miscibility increases.<unk> -water mixtures have less volume than the sum of their individual components at the given fractions. Mixing equal volumes of<unk>  and water results in only 1.92 volumes of mixture. Mixing<unk>  and water is exothermic, with up to 777 J/mol being released at 298 K. Mixtures of<unk>  and water form an azeotrope at about 89 mole-%<unk>  and 11 mole-% water or a mixture of 95.6 percent<unk>  by mass (or about 97% alcohol by volume) at normal pressure, which boils at 351K (78 °C). This azeotropic composition is strongly temperature- and pressure-dependent and vanishes at temperatures below 303 K. Hydrogen bonding in solid<unk>  at −186 °C Hydrogen bonding causes pure<unk>  to be hygroscopic to the extent that it readily absorbs water from the air. The polar nature of the hydroxyl group causes<unk>  to dissolve many ionic compounds, notably sodium and potassium hydroxides, magnesium chloride, calcium chloride, ammonium chloride, ammonium bromide, and sodium bromide. Sodium and potassium chlorides are slightly soluble in<unk> . Because the<unk>  molecule also has a nonpolar end, it will also dissolve nonpolar substances, including most essential oils and numerous flavoring, coloring, and medicinal agents. The addition of even a few percent of<unk>  to water sharply reduces the surface tension of water. This property partially explains the "tears of wine" phenomenon. When wine is swirled in a glass,<unk>  evaporates quickly from the thin film of wine on the wall of the glass. As the wine's<unk>  content decreases, its surface tension increases and the thin film "beads up" and runs down the glass in channels rather than as a smooth sheet. Flammability An<unk> –water solution will catch fire if heated above a temperature called its flash point and an ignition source is then applied to it. For 20% alcohol by mass (about 25% by volume), this will occur at about . The flash point of pure<unk>  is , but may be influenced very slightly by atmospheric composition such as pressure and humidity.<unk>  mixtures can ignite below average room temperature.<unk>  is considered a flammable liquid (Class 3 Hazardous Material) in concentrations above 2.35% by mass (3.0% by volume; 6 proof). : + Flash points of<unk> –water mixtures<unk>  mass fraction, % Temperature °C °F 1 2 2.35 3 5 6 10 20 30 40 50 60 70 80 90 100 Dishes using burning alcohol for culinary effects are called flambé.
Ethanol
Chloroethane
Chloroform
Ethylene glycol
Dichloromethane
Trihalomethane
Diethyl ether
Perfluorooctanoic acid