Methanoic acid is normally found in:
- A.muscles
- B.urine
- C.ant stings
- D.human brain
Correct answer
Explanation
The correct answer is C, ant stings. Methanoic acid, better known as formic acid, is the acid that ants inject when they sting, which is why the bite burns.
Methanoic acid (HCOOH) is the simplest carboxylic acid. Its common name, formic acid, comes from the Latin word formica, meaning ant, because it was first obtained by distilling ants in the seventeenth century. Ants, bees and the stinging hairs of the nettle plant all deliver it. Rubbing a mild base such as baking soda solution on the spot neutralises the acid and reduces the pain. Industrially it is used in leather tanning and as a coagulant for rubber latex.
A is wrong: muscles build up lactic acid during hard exercise, not methanoic acid.
B is wrong: urine mainly contains urea and uric acid along with salts.
D is wrong: methanoic acid is not a normal component of the human brain.
Exam tip: formica = ant, so formic acid = ant sting; lactic acid = muscles and curd; uric acid = urine and gout.
Practice Questions
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- C.barometer
- D.anemometer
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- A.0-200 Hz
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- C.200-20,000 Hz only
- D.2,000-20,000 Hz only
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