Methanal, HCHO, is used in a 40 per cent aqueous solution known as formalin, mainly for
- A. preserving biological specimens
- B. flavouring food
- C. treating drinking water
- D. use as a fuel
Explanation
Methanal cross links the proteins of tissue, hardening it and killing microorganisms, which is why formalin preserves specimens and is also used to make thermosetting resins such as bakelite. It is a gas at room temperature, so the aqueous solution is the practical form. The compound is toxic and is now treated as a carcinogen, so exposure is controlled.