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Chemistry with a wicked sense of humor

Toxic Trivia

Ten questions. A few familiar molecules. One potentially insulting ranking.

10 questions10 possible pointsInstant feedback

Answer every question, then select Grade my quiz for your score, your original Toxic Trivia ranking and hints. Correct answers unlock explanations with sources. Change your answers and grade again whenever you like.

Each question is worth one point. For matching, ranges and ranking, every entry must be correct to earn the point; questions 3 and 6 give feedback on each entry; question 4 reports only the number correct until all eight ranges are right.

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1 Spot the decongestant

Which structure is ephedrine, a compound historically used as a nasal decongestant?

These are structural identification questions, not recommendations for taking medicines. In these drawings, carbon atoms occur at unlabeled corners and line ends; most hydrogens on carbon are omitted.

2 A little goes a long way

One of the most dangerous radioactive isotopes to take into the body is 210Po (polonium-210). It is a strong alpha emitter with a half-life of about 138 days. It occurs naturally in trace amounts and is present in tobacco smoke; alpha-emitting material inside the body can damage nearby tissue.

Its radioactive decay releases energy as well as radiation. An amount far too small to see can have serious consequences when taken into the body.

Let’s compare it with hydrogen cyanide—in theory, using mass alone. For this illustration, use two reported oral toxicity figures for rats: 4.2 mg/kg for hydrogen cyanide (an LD50) and 8.7 nanograms/kg for polonium-210 (a reported dose associated with death after about 30 days, not an established LD50).

Based only on those figures, in theory, how many times more deadly is polonium-210 than hydrogen cyanide by mass?

3 Name that molecule

Match each name to a structure labeled A–I. Use each name once.

All nine matches must be correct to earn this question’s one point.

Drag a name onto a structure, or select a name and then select its destination. Keyboard: Tab to a name, press Enter, then Tab to a destination and press Enter. To clear a name or occupied slot, press Delete or Backspace; you can also drag it back to the bank.

Structure A: Two fused rings with four nitrogens, two carbonyl groups and three N-methyl groups.
Structure A
Structure B: Four fused rings, one ketone and one hydroxyl group.
Structure B
Structure C: Four fused rings with an aromatic ring and two hydroxyl groups.
Structure C
Structure D: Four fused rings with one hydroxyl group and a branched alkyl side chain.
Structure D
Structure E: A fused beta-lactam and sulfur-containing ring, a carboxylic acid and a phenoxyacetamide side chain.
Structure E
Structure F: A bicyclic N-methyl ring with benzoate and methyl ester groups.
Structure F
Structure G: Two para-chlorophenyl groups bonded to a carbon next to a trichloromethyl group.
Structure G
Structure H: A para-amino benzoate ester linked to a two-carbon chain and a diethylamino group.
Structure H
Structure I: A thymine base attached to a sugar-like ring bearing a hydroxymethyl group and an azide group.
Structure I
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4 Risk, by the numbers

Choose the range containing each U.S. death count or estimate. Use the year and definition shown; the rows cover different time periods and are not additive.

All eight ranges must be correct to earn this question’s one point.

5 The dose makes the poison

Most people have heard that if a rat eats a substance that makes it sick, the rat will avoid that substance in the future (something many of us learn about with alcohol…). Therefore, one has to be clever in designing a rat poison.

Warfarin has been a particularly effective rat poison even though it is not what one normally considers highly toxic. Warfarin is an anticoagulant: it interferes with blood clotting, causing poisoned rats to hemorrhage (bleed internally) and slowly die. The effects are delayed, so rats can eat bait and return for more before becoming ill.

Curiously, warfarin is also prescribed for medical use in humans (“the dose makes the poison”)! Which one of these medical conditions can NOT be treated effectively with warfarin?

Chemical structure of warfarin
6 Six reported LD₅₀ values

Arrange these six substances along the scale, from 6 (smallest reported oral LD50) at the top to 1 (largest) at the bottom. A smaller LD50 means a smaller dose killed half the test animals.

This compares selected published values: rats except tetrodotoxin (mice). It is not a universal toxicity ranking or a human safe-dose guide; species, exposure route and study conditions matter.

Use each substance once. All six positions must be correct to earn this question’s one point.

Drag a substance onto the scale, or select a substance and then select its position. The same controls work with Tab and Enter. Press Delete or Backspace on a name or occupied slot to clear it, or drag it back to the bank.

Smallest LD50 · greater acute toxicity in these tests

6
5
4
3
2
1

Largest LD50 · lower acute toxicity in these tests

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7 One molecule, two medicine cabinets

Diphenhydramine is the active ingredient in certain over-the-counter antihistamines such as Benadryl™. Its structure is shown here on the right. Diphenhydramine is also the active ingredient in what other popular medication?

Chemical structure of diphenhydramine
8 An indicator with a past

Phenolphthalein is an acid-base indicator. It turns pink above about pH 8.5 and is colorless below that (more on the pH scale here). Phenolphthalein had another use until 1999, when it was withdrawn from the U.S. market for that use over carcinogenicity concerns. What was this use?

Chemical structure of phenolphthalein
9 A warning on the label

Phenylalanine is an amino acid that the body uses to make proteins and as a precursor to other compounds, including neurotransmitters. It is not produced by the body, so we must obtain it from dietary sources such as eggs, milk and nuts.

Unfortunately, some people have a hereditary disorder called phenylketonuria (PKU), an inability to properly metabolize phenylalanine. This is particularly dangerous in children, as excess phenylalanine can interfere with brain development. Newborn screening can identify PKU shortly after birth. With early treatment and appropriate dietary management, people with PKU can lead healthy lives.

In the 1980s, a new consumer food ingredient was approved for use in a growing range of products. It is a source of phenylalanine, posing a risk to people with PKU who might unwittingly consume it. A phenylalanine warning had already been required as a condition of its original 1974 FDA approval. For the general population, FDA considers this ingredient safe under its approved conditions of use.

What is this ingredient?

Chemical structure of L-phenylalanine
10 A beautiful, poisonous green

In the early 1800s, a wonderfully vivid green pigment called Paris green was developed. Also known as emerald green, it was used in consumer products, including wallpaper and textiles, and later as an insecticide. Unfortunately, its beautiful color came with an unwelcome ingredient: arsenic.

During the nineteenth century, illnesses and deaths were blamed on rooms decorated with arsenic-containing green wallpapers. Damp walls and mold attracted particular suspicion: microorganisms can transform arsenic compounds into volatile forms. Arsenic-bearing dust from deteriorating wallpaper was another possible route of exposure.

The familiar explanation involving a poisonous gas called trimethylarsine remains disputed; later research challenged its supposed extreme toxicity. The evidence does not establish one mechanism for every historical case. But retiring to a bedroom decorated with arsenical wallpaper was hardly an ideal way to escape a suspected exposure!

Which of these is the chemical composition of Paris green?