Dyes are added to denatured alcohol to color it blue, making it easily distinguishable from consumable ethanol. This helps prevent accidental ingestion of the toxic denatured alcohol.

Methanol is added to ethanol produced for industrial use to render it unfit for consumption. This prevents the misuse of industrial ethanol for drinking purposes.

Methanol is far more toxic than ethanol. Even very small quantities of methanol can be lethal. Methanol is oxidized to methanal (formaldehyde) in the liver, which then rapidly reacts with cellular components, coagulating protoplasm and affecting the optic nerve, potentially ...

Consuming large quantities of ethanol can slow metabolic processes and depress the central nervous system, leading to lack of coordination, mental confusion, drowsiness, lowered inhibitions, and ultimately stupor.

The general chemical equation for the reaction between metals and acids to produce hydrogen gas is: Metal + Acid → Salt + Hydrogen gas