An excess consumption of which of these compounds causes blindness and death?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Methanol
Methanol (\( \ce{CH3OH} \), wood spirit) is highly poisonous. In the body it is oxidised first to methanal and then to methanoic acid, which act on the optic nerve. Even small quantities of methanol can cause blindness, and large quantities cause death. This is why methanol is added to denature industrial ethanol and why spurious liquor containing methanol is so dangerous.
Why the other options are incorrect
Option (2) Ethanol — Incorrect. Ethanol is the alcohol of alcoholic drinks; in the body it is oxidised to ethanal and then ethanoic acid. It harms the liver in excess but does not cause blindness.
Option (3) Methanal — Incorrect. Methanal (formaldehyde) is a toxic intermediate formed in the body from methanol; the question asks for the compound whose drinking causes blindness and death, which is the alcohol methanol.
Option (4) Methanoic acid — Incorrect. Methanoic acid is a product of the oxidation of methanol in the body, not the substance consumed.
NCERT (2026-27 edition):
Methanol – …
