Science quiz: Chemistry’s foul fellows

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Name the molecule depicted by this ball-and-stick model. It’s responsible for vinegar’s odour and imparts its sour taste.

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X is a colourless gas that smells like garlic or fish, especially when it contains impurities. Scientists have linked it to rotting organic matter in places with low oxygen. In 2020, researchers said they detected X in Venus’s atmosphere, hinting at unusual chemistry, but later studies dismissed it. Name X.

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Name the colourless gas notorious in high-school chemistry labs for smelling like rotten eggs. It’s produced when bacteria break down one of its constituent elements in the absence of oxygen. It can also appear near sewage systems and volcanic vents and is toxic even at low concentrations.

4 / 6 |
_____ gas has a sharp ‘electrical’ smell that people sometimes notice after lightning storms or near some machines with sparking. It’s a compound made of three atoms of the same element. The 1987 Montreal Protocol was created to help protect this gas’s presence in the upper atmosphere. Fill in the blank.

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This element is a dark reddish-brown liquid at room temperature and gives off a strong and irritating vapour. It belongs to the family of halogens on the periodic table. People used to use it in the first photography techniques and also in some flame retardants. Name it.

6 / 6 |
Y is a simple compound, in fact the smallest aldehyde, and it’s widely used to preserve biological specimens and in some building materials. It has a strong, sharp archetypically chemical smell and can irritate the eyes and the throat, especially in poorly ventilated spaces. Name Y.