Methanol is toxic because (a) methanol coagulates the protoplasm (b) methanol gets oxidised to methanal in liver which coagulates the protoplasm (c) methanol gets oxidised to acetic acid in liver which coagulates the protoplasm (d) methanol gets oxidised to CO in liver which coagulates the protoplasm

Methanol (methyl alcohol) is highly toxic even in small quantities. When ingested, it is primarily metabolized in the liver, where the enzyme alcohol dehydrogenase oxidizes it into methanal, also known as formaldehyde [1]. Methanal is a highly reactive compound that rapidly interacts with cellular components. Specifically, it causes the coagulation of protoplasm in a manner similar to how heat coagulates an egg [1]. While methanal is further oxidized to formic acid (methanoic acid), which leads to metabolic acidosis and optic nerve damage [1], the specific mechanism of cellular destruction via protoplasm coagulation is attributed to the intermediate methanal [1]. This process disrupts cellular integrity and function, leading to severe systemic toxicity and potentially death [2].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 4: Carbon and its Compounds > How do alcohols affect living beings? > p. 72