Methylated spirit contains ethanol and is available cheaply. Methylated spirit also contains:
pyridine which has a very unpleasant smell
methyl violet which makes the mixture purple
Suggest why pyridine and methyl violet are added to ethanol to make methylated spirit.
How to approach this question
Ethanol is the alcohol found in alcoholic drinks. Methylated spirit is sold cheaply for use as a fuel or solvent. Consider why manufacturers would want to prevent people from drinking this industrial-grade ethanol. How do the properties of pyridine (unpleasant smell) and methyl violet (purple colour) help achieve this?
Full Answer
Ethanol is the type of alcohol consumed in alcoholic beverages. Pure ethanol for consumption is subject to high taxes. Methylated spirit is essentially ethanol intended for industrial use (as a solvent or fuel) and is sold much more cheaply, without the high taxes. To prevent people from buying it and drinking it to avoid the alcohol tax, additives are used to make it "denatured" or unfit for consumption.
- **Pyridine** is added because it has a foul smell and taste.
- **Methyl violet** is a purple dye added as a visual warning that the liquid is not for drinking.
- **Methanol** (also present) is highly toxic.
Common mistakes
✗ Just stating the properties (e.g., "to make it smell bad") without explaining the purpose (to stop people drinking it).
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