Toxic

Malay: Toksik · Chinese: 有毒

Toxic describes a chemical that is poisonous if it is taken into the body, by being swallowed, breathed in, or absorbed through the skin. The danger is what happens inside the body, so a toxic substance can cause serious harm even in a small amount that enters through the mouth, the lungs or the skin. Because of this, toxic chemicals are handled with great care and often used inside a fume cupboard so that harmful vapours are drawn away. The SPM Chemistry papers (4541) expect you to link the toxic symbol to precautions like these.

For example, when working with a toxic substance you never taste it, you smell it only by gentle wafting rather than putting it near your nose, you keep it in a fume cupboard if it gives off vapour, and you wash your hands afterwards. Each of these keeps the chemical from getting into your body, which is exactly where its danger lies. You also avoid eating or drinking in the laboratory, so that a toxic substance is never carried to the mouth on the hands or on food.

The confusion to avoid, the classic paired distinction of this chapter, is between toxic and corrosive. Toxic means poisonous once taken in; corrosive means damaging on contact. A corrosive acid burns the skin at once, whereas a toxic substance may look harmless yet poison you if it enters the body. Choosing the wrong word means giving the wrong precaution, so keep “taken in” versus “on contact” firmly apart.

Within the safety section, toxic joins corrosive and flammable as the hazard classes behind the fume cupboard, goggles and wafting, and it is read from the toxic hazard symbol on the container. Our teachers keep the toxic-versus-corrosive pair sharp so your safety answers score reliably.