How does potassium cyanide work? --- Neeraj, Mumbai, India
If you have a chemical that contains a nitrogen atom with a triple bond to a carbon atom, then you have a cyanide. Potassium cyanide contains one potassium, one carbon and one nitrogen atom (KCN). Potassium cyanide forms a white powder.
The most infamous use of potassium cyanide is in suicide pills. The cyanide is placed in a small glass capsule. You have to crush the capsule with your teeth and swallow, and the cyanide causes death in a few minutes.
The reason cyanide causes death is because it interrupts a cellular process that creates ATP. Most cells use ATP as a source of energy. In the nervous system, ATP is the only source of energy. Once ATP production shuts down, cell death is almost immediate. For more info see: How Poisons Work