Question

Intake of small quantities of methanol can be lethal. Comment

Answer 1

Hint:Methanol gets converted to Methanal and liver and kills all the cells. Methanol also affects the optic nerves and causes blindness. Hence intake of small quantities of methanol can be lethal.

Complete step by step answer:
Methanol is very poisonous because it is oxidized to methanol in the liver. Methanol reacts rapidly with the components of cells and causes the protoplasm to get coagulated (in the same ways, as an egg gets coagulated on boiling). Methanol also affects the optic nerve causing blindness.
Oxidation of methanol in the liver:-Methanol is oxidized in the liver to formaldehyde. The enzyme responsible for this process varies from species to species. Alcohol dehydrogenase is preponderant in most primates, and a catalase peroxidase complex predominates in rodents, humans, and possibly some other species. Formaldehyde is rapidly oxidized to formic acid by formaldehyde dehydrogenase. Formic acid is responsible for the delayed clinical signs of methanol toxicosis in humans and other primates. Formic acid acidosis directly and indirectly in primates through cytochrome C oxidase inhibition, which interferes with aerobic metabolism. Inhibition of mitochondria cytochrome is also responsible for the CNs effects. Formic acid is metabolized relatively rapidly to carbon dioxide and water by an enzyme system that depends on tetrahydrofolate in most domestic species, but this enzyme system is deficient in humans and some primates

Note:
A person’s liver processes ethanol first instead of methanol poisoning and allows for more time to process methanol out of a person’s system. Administration of sodium bicarbonate can also neutralize formic acid and maintain proper pH balance.