A friend’s dad recognised cyanide during a chemistry exam by tasting it. (He survived and passed the exam.)
The task was to say what each of n substances given were in a short enough amount of time, filling out a report. I’m not sure if they still give cyanide to students during exams. That was communist Poland.
He's lucky that he could smell it! About 1/3 of the population lack the gene -- including my grandfather, who discovered this when performing an industrial reaction with cyanides and being alerted by someone at the other end of the room yelling that he could smell cyanide.
Hydrogen sulfide generally repels people to a safe distance due to its strong smell of rotten eggs, but in very high doses, such as when the police open a car door after an H2S suicide within, it quickly disables that very sense of smell.
The task was to say what each of n substances given were in a short enough amount of time, filling out a report. I’m not sure if they still give cyanide to students during exams. That was communist Poland.