50 Fun Facts About Organic Chemistry

Which ring-shaped molecule did August Kekulé say he pictured after daydreaming of a snake seizing its own tail?

Benzene had been isolated by Michael Faraday in 1825 from the oily residue of gas lighting, 40 years before Kekulé proposed its ring of six carbons.

Which sedative sold for morning sickness around 1960 caused thousands of birth defects and led to stricter drug rules?

Thalidomide is made as a 50:50 mix of mirror-image molecules, and the body converts each form into the other. So a pill of just one form would still end up as both.

Which DuPont material was discovered by accident in 1938 inside a gas bottle lined with a slippery white wax?

Teflon came from a failed experiment: Roy Plunkett's team was trying to make a new refrigerant when the gas in the bottle turned solid. An early use was coating valves and seals in the Manhattan Project's uranium plant.

Which gas, the simplest alkene, doubles as a natural plant hormone that farmers use to ripen fruit?

Ethylene showed its power over plants in the 19th century, when gas leaking from street lights stunted nearby growth and made leaves fall early. Scrubbing it from storage rooms delays the ripening of harvested fruit.

Which French chemist opened the study of mirror-image molecules by manually sorting two shapes of tartrate crystal?

Louis Pasteur was the first to produce a pure sample of one mirror-image form, picking the crystals apart by their shape. His famous work on germs and vaccines came later.

Which compound, sprayed by wood ants to defend their nests, is named after the Latin word for ant?

Formic acid was first described in 1671, when the naturalist John Ray obtained it from large numbers of ants. Its systematic name is methanoic acid.

Which common painkiller, known to chemists as acetylsalicylic acid, traces back to a remedy found in willow bark?

Aspirin was first made in a pure, stable form at Bayer in 1897, but the willow remedies behind it have been used for at least 2,400 years.

What is the name of the reaction in which fats or oils are treated with lye to release glycerol and soap?

Saponification takes its name from sapo, the Latin word for soap. Using sodium hydroxide as the lye produces hard soaps.

Which type of fat, named for hydrogens on opposite sides of a double bond, forms when oils are partly hydrogenated?

Trans fats have straight chains, unlike the cis fats usual in nature. Linked to heart disease, the artificial kind was banned from food sold in the US from 2018.

Which compound, the main nitrogen waste in mammals, did Friedrich Wöhler make from inorganic starting materials in 1828?

Urea from a flask showed that a substance of living things could be built from mineral ingredients. Wöhler boasted to Berzelius that he could make it without kidneys, man or dog.

Which compound gives vinegar, a condiment made since the third millennium BCE, its sour taste?

Acetic acid freezes just below room temperature into ice-like crystals, which is why the pure, water-free liquid is called glacial.

Which alcohol, made when yeast ferments sugar, is the active ingredient in beer, wine and spirits?

Ethanol is the second most consumed drug in the world, behind only caffeine. Yeast makes it wherever it lives, so traces turn up naturally in overripe fruit.

Which simplest hydrocarbon, the main ingredient of natural gas, is also belched into the air by cattle?

Methane releases more heat per gram when burned than more complex hydrocarbons. Loose in the atmosphere, it absorbs infrared radiation and acts as a greenhouse gas.

Which hydrocarbon lends its name to the anti-knock rating shown on fuel pumps?

Octane ratings compare a fuel with blends of iso-octane and heptane. Fuel rated 90 resists engine knock as well as a blend that is 90% iso-octane.

Which plastic, the most commonly produced in the world, is used mainly for packaging such as bags, films and bottles?

Polyethylene was discovered by accident twice: in a German lab in 1898, then in 1933 at ICI in England, the find that led to its industrial production.

Which sugar with the formula C6H12O6 circulates in the blood of animals as blood sugar?

Glucose is the most abundant simple sugar in nature, and plants chain it into cellulose for their cell walls. An adult's blood holds only about 4 grams of it.

Which solvent in many nail polish removers is the simplest ketone, known systematically as propanone?

Acetone is also made by the human body, forming in tissue during prolonged fasting or a high-fat, low-carbohydrate diet.

Which pungent gas, the simplest aldehyde, is dissolved in water to preserve tissue samples and embalm bodies?

Formaldehyde was the first polyatomic organic molecule detected in interstellar space. On Earth it mainly goes into industrial resins for particle board and coatings.

Butane and methylpropane share the formula C4H10 but have different structures, a relationship that makes them what?

Isomers were first noticed in the 1820s, when silver cyanate and silver fulminate turned out to have identical compositions but distinct properties. Berzelius named the phenomenon in 1830.

Which technique do oil refineries use to separate crude oil into fuels such as gasoline and kerosene by boiling point?

Fractional distillation sends the lightest products out of the top of the tower and the heaviest out of the bottom, with outlets in between drawing off each fuel.

Which functional group is flagged by the suffix -ol in names such as cholesterol and paracetamol?

Hydroxyl groups mark a compound as an alcohol, though not every one advertises it: sugars such as sucrose carry several without an -ol in their names.

Which functional group, written C=O, lies at the heart of both aldehydes and ketones?

Carbonyl carbons are short of electrons, which makes them a prime target for attack in many reactions. Those in aldehydes are more reactive than those in ketones.

Which functional group, formed when an acid reacts with an alcohol, gives pears, bananas and pineapples their aroma?

Ester names end in -ate, as in the acetates and butyrates prized by the flavor and fragrance industry. The small ones often have a pleasant, fruity smell.

Which nitrogen-containing functional group makes organic compounds basic and gives decaying fish its distinctive smell?

Amine molecules are ammonia with one or more of its hydrogens swapped for carbon groups. The stench of old fish is one of them, released as the flesh breaks down.

Which functional group forms the peptide bonds of every protein and joins the repeating units of Kevlar?

Amide links resist water well enough to hold a protein's structure together inside a living cell, yet enzymes can still cut them when needed.

Which functional group, an oxygen atom bonded to two carbons, names the anesthetic demonstrated in Boston in 1846?

Ether for surgery was promoted by William Morton under the name Letheon, after the mythical river of forgetfulness, with aromatic oils added to hide its smell.

Despite the -ene ending of its common name, welding gas acetylene belongs to which family of triple-bonded hydrocarbons?

Alkynes show their family ending in the gas's systematic name, ethyne. Its triple bond stores a great deal of energy and holds all four atoms in a straight line.

Which sulfur-containing group gives skunk spray its stench and is added to natural gas so leaks can be smelled?

Thiol odorants became compulsory in American gas after a deadly 1937 school explosion in New London, Texas. The group's older name, mercaptan, means 'capturing mercury'.

Which mirror-image molecules share their physical properties but rotate polarized light in opposite directions?

Enantiomers are like left and right hands: one cannot be laid over the other. In the body, the two forms of a compound can have substantially different effects.

Which property, named by Lord Kelvin from the Greek for hand, means an object differs from its mirror image?

Chirality is easy to feel: try shaking someone's right hand with your left, or pulling a left-handed glove onto a right hand.

What term describes a 50:50 blend of a molecule's left- and right-handed forms, which cannot rotate polarized light?

A racemic mixture gets its name from the Latin racemus, a bunch of grapes. Its two halves twist light in opposite directions, so the rotations cancel out.

In the R/S system for labeling a stereocenter, the letter S abbreviates which Latin word?

Sinister, Latin for left, marks a stereocenter whose groups run counterclockwise in order of priority, a ranking set by atomic number. Its partner R stands for rectus.

The two mirror-image forms of carvone smell different: one like spearmint leaves, the other like which seed?

Caraway and spearmint carry opposite hands of the same molecule. That the nose can tell them apart is evidence that smell receptors respond more strongly to one form than the other.

Which conformation do more than 99% of the molecules in cyclohexane adopt at 25 °C, making it the most stable shape?

Chair cyclohexane was central to the work that won Derek Barton and Odd Hassel the 1969 Nobel Prize in Chemistry. Its hydrogens split into six axial and six equatorial positions.

Which shape, proposed by van 't Hoff and Le Bel in 1874, do the four single bonds around a carbon atom form?

Tetrahedral carbon was largely ignored at first and sharply criticized by the prominent chemist Hermann Kolbe. Van 't Hoff went on to win the first Nobel Prize in Chemistry.

Which concept, developed by Linus Pauling from 1928, treats a molecule as an average of several drawn structures?

Resonance theory was attacked in the Soviet Union in the early 1950s as contrary to Marxist principles. The real molecule is a single average of the drawn forms, not a flicker between them.

Which term describes the alternating single and double bonds that give beta-carotene and many dyes their strong color?

Conjugation spreads electrons along the chain, and the longer the run, the longer the wavelength of light it can absorb. That is how beta-carotene's long chain turns out orange.

Which measure of acid strength, a logarithmic form of the dissociation constant, is lower for stronger acids?

pKa equals the pH at which exactly half of an acid has given up its proton. Each unit lower on the scale means an acid ten times stronger.

Which American chemist gives his name to acids defined as electron-pair acceptors rather than proton donors?

Gilbert N. Lewis also gave chemistry the dot diagram and the shared-pair covalent bond, yet he never received a Nobel Prize despite being nominated 41 times.

Whose rule predicts that when HBr adds to an alkene, the hydrogen joins the carbon already holding more hydrogens?

Vladimir Markovnikov's rule works because the addition runs through the most stable carbocation, the one on the more substituted carbon.

Which organomagnesium compound, a Nobel-winning discovery of 1900, builds alcohols by attacking aldehydes and ketones?

A Grignard reagent is rapidly destroyed by water or air, so the reaction must be kept dry. Victor Grignard's discovery brought him the Nobel Prize in 1912.

Which reaction, a Nobel winner in 1950, joins a diene to an alkene in one step to build a six-membered ring?

Diels–Alder chemistry builds two new carbon–carbon bonds at once. Otto Diels and Kurt Alder reported it in 1928 and later shared the Nobel Prize for it.

Which reactions, developed in 1877, attach carbon groups to an aromatic ring using an aluminum chloride catalyst?

Friedel–Crafts reactions are named for their developers, Charles Friedel and James Crafts, and come in two main types: alkylation and acylation.

Which one-step reaction mechanism inverts a carbon's configuration, like an umbrella turned inside out in a gale?

SN2 stands for substitution, nucleophilic, bimolecular: both reacting species take part in the rate-determining step. The newcomer attacks from the back as the leaving group departs.

Which reaction cleaves an alkene at its double bond, replacing it with two carbon–oxygen double bonds?

Ozonolysis does the cutting with ozone, the gas that shields Earth from ultraviolet rays. Before modern spectroscopy, it was an important way to work out the structure of organic molecules.

Whose reagent reveals aldehydes by coating the inside of the reaction vessel with a mirror of metallic silver?

Bernhard Tollens's reagent is also used to silver glassware, such as the inside of an insulated vacuum flask. Most ketones leave it unchanged.

Which mild hydride, found in the 1940s during a hunt for uranium compounds, reduces aldehydes and ketones to alcohols?

Sodium borohydride is gentle enough to be used in water or alcohol, where it breaks down only slowly. Its stronger cousin lithium aluminum hydride attacks far more functional groups.

Which chromium oxidant, known by a three-letter abbreviation, turns a primary alcohol into an aldehyde and stops there?

PCC, short for pyridinium chlorochromate, is a yellow-orange salt also called the Corey–Suggs reagent. Kept free of water, it has little chance of overshooting to the carboxylic acid.

Whose rule says a flat ring is aromatic only if it holds 4n + 2 pi electrons, such as six?

Erich Hückel worked out the quantum mechanics behind the rule in 1931. Cyclobutadiene, with four such electrons, breaks it and survives only below 35 kelvin.

Which notation, developed by Robert Robinson in 1922, tracks electron pairs as they move through a reaction mechanism?

Curved arrows with a double barb show a pair of electrons moving, while a single barb follows one electron traveling on its own.