Methanol is toxic because  

The correct answer is Option 2.

Key PointsWhy Methanol is Toxic?

• Methanol, also known as wood alcohol, is a toxic chemical that, when ingested, inhaled, or absorbed through the skin, can lead to serious health complications and potentially death.
• The primary reason for its toxicity is its metabolism within the human body, where methanol is oxidised to methanal (formaldehyde) by liver enzymes.
• Formaldehyde is highly toxic and can cause protein coagulation. This means it can denature proteins, leading to cellular dysfunction and cell death.
• The toxic effects of methanol poisoning can include visual disturbances, headaches, dizziness, and in severe cases, coma, and death.
• Treatment for methanol poisoning includes the administration of ethanol or fomepizole, which have a higher affinity for the alcohol dehydrogenase enzyme, thus preventing the metabolism of methanol to its toxic metabolites.

Hence, statement 2 is correct.

Additional Information

• Methanol is often used in industrial applications, including as a solvent and antifreeze. Its use in homemade alcoholic beverages can lead to outbreaks of poisoning.
• The body metabolizes methanol using the enzyme alcohol dehydrogenase, which also metabolizes ethanol, the type of alcohol typically found in alcoholic beverages. This is why ethanol is used as an antidote because it competes with methanol for the same enzyme, reducing the rate at which methanol is metabolized into toxic compounds.
• Healthcare providers may also use hemodialysis to remove methanol and its metabolites from the blood of affected individuals.
• Preventive measures include ensuring industrial methanol is denatured and properly labeled to prevent accidental ingestion and implementing strict regulations on alcoholic beverage production.