Commercial alcohol is made unfit for drinking by mixing in it some copper sulphate and pyridine. Which of the following correctly gives the purpose of each?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Copper sulphate gives it a colour; pyridine gives it a foul smell
Making commercial alcohol unfit for drinking is called denaturation of alcohol. Copper sulphate is added to give it a colour, and pyridine, a foul smelling liquid, is added to give it a bad smell.
NCERT (2026-27 edition):
7.5 Some Commercially Important Alcohols – “…The commercial alcohol is made unfit for drinking by mixing in it some copper sulphate (to give it a colour) and pyridine (a foul smelling liquid). It is known as denaturation of alcohol.”