Organic Chemistry
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50 free Organic Chemistry trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Organic chemistry is the chemistry of carbon, and it explains a surprising amount of daily life: why vinegar is sour, why skunks stink, how soap gets made, and why one accidental discovery after another ended up in the kitchen or the medicine cabinet. It is also the course with a reputation, a wall of functional groups, named reactions and reagents that students have to know cold. This quiz covers the ground an organic chem class does. There are questions on spotting functional groups and the families they define, on the rules for naming compounds, and on stereochemistry, where a molecule and its mirror image can behave very differently. Others deal with acids and bases, with how electrons spread across a molecule, and with the reactions, mechanisms and reagents that fill a second-semester exam. The stories are here too: the dreams, lucky accidents and Nobel Prizes behind the molecules. The opening questions suit anyone who remembers a little school chemistry, and the later ones are pitched at students revising for an orgo test. Every answer comes with a short explanation, so a wrong guess still teaches you something.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which ring-shaped molecule did August Kekulé say he pictured after daydreaming of a snake seizing its own tail?
Benzene
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.
Q 02Which sedative sold for morning sickness around 1960 caused thousands of birth defects and led to stricter drug rules?
Thalidomide
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.
Q 03Which DuPont material was discovered by accident in 1938 inside a gas bottle lined with a slippery white wax?
Teflon
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.
Q 04Which gas, the simplest alkene, doubles as a natural plant hormone that farmers use to ripen fruit?
Ethylene
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.
Q 05Which French chemist opened the study of mirror-image molecules by manually sorting two shapes of tartrate crystal?
Louis Pasteur
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.
Q 06Which compound, sprayed by wood ants to defend their nests, is named after the Latin word for ant?
Formic acid
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.
Q 07Which common painkiller, known to chemists as acetylsalicylic acid, traces back to a remedy found in willow bark?
Aspirin
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.
Q 08What is the name of the reaction in which fats or oils are treated with lye to release glycerol and soap?
Saponification
Saponification takes its name from sapo, the Latin word for soap. Using sodium hydroxide as the lye produces hard soaps.
Q 09Which type of fat, named for hydrogens on opposite sides of a double bond, forms when oils are partly hydrogenated?
Trans fats
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.
Q 10Which compound, the main nitrogen waste in mammals, did Friedrich Wöhler make from inorganic starting materials in 1828?
Urea
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.
Q 11Which compound gives vinegar, a condiment made since the third millennium BCE, its sour taste?
Acetic acid
Acetic acid freezes just below room temperature into ice-like crystals, which is why the pure, water-free liquid is called glacial.
Q 12Which alcohol, made when yeast ferments sugar, is the active ingredient in beer, wine and spirits?
Ethanol
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.
Q 13Which simplest hydrocarbon, the main ingredient of natural gas, is also belched into the air by cattle?
Methane
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.
Q 21Which functional group is flagged by the suffix -ol in names such as cholesterol and paracetamol?
Hydroxyl
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.
Q 22Which functional group, written C=O, lies at the heart of both aldehydes and ketones?
Carbonyl
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.
Q 23Which functional group, formed when an acid reacts with an alcohol, gives pears, bananas and pineapples their aroma?
Ester
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.
Q 14Which hydrocarbon lends its name to the anti-knock rating shown on fuel pumps?
Octane
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.
Q 15Which plastic, the most commonly produced in the world, is used mainly for packaging such as bags, films and bottles?
Polyethylene
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.
Q 16Which sugar with the formula C6H12O6 circulates in the blood of animals as blood sugar?
Glucose
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.
Q 17Which solvent in many nail polish removers is the simplest ketone, known systematically as propanone?
Acetone
Acetone is also made by the human body, forming in tissue during prolonged fasting or a high-fat, low-carbohydrate diet.
Q 18Which pungent gas, the simplest aldehyde, is dissolved in water to preserve tissue samples and embalm bodies?
Formaldehyde
Formaldehyde was the first polyatomic organic molecule detected in interstellar space. On Earth it mainly goes into industrial resins for particle board and coatings.
Q 19Butane and methylpropane share the formula C4H10 but have different structures, a relationship that makes them what?
Isomers
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.
Q 20Which technique do oil refineries use to separate crude oil into fuels such as gasoline and kerosene by boiling point?
Fractional distillation
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.
Q 24Which nitrogen-containing functional group makes organic compounds basic and gives decaying fish its distinctive smell?
Amine
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.
Q 25Which functional group forms the peptide bonds of every protein and joins the repeating units of Kevlar?
Amide
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.
Q 26Which functional group, an oxygen atom bonded to two carbons, names the anesthetic demonstrated in Boston in 1846?
Ether
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.
Q 27Despite the -ene ending of its common name, welding gas acetylene belongs to which family of triple-bonded hydrocarbons?
Alkynes
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.
Q 28Which sulfur-containing group gives skunk spray its stench and is added to natural gas so leaks can be smelled?
Thiol
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'.
Q 29Which mirror-image molecules share their physical properties but rotate polarized light in opposite directions?
Enantiomers
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.
Q 30Which property, named by Lord Kelvin from the Greek for hand, means an object differs from its mirror image?
Chirality
Chirality is easy to feel: try shaking someone's right hand with your left, or pulling a left-handed glove onto a right hand.