What properties of sulfuric acid require extremely careful handling? What rule should be followed when diluting sulfuric acid?

Sulfuric acid dissolves in water, releasing a large amount of heat.
While preparing the solution, sulfuric acid is poured into water in a thin stream (and not vice versa!) With constant stirring.
Why? If you add water to a concentrated acid, due to the heat released, the water boils and can throw acid splashes on the face and hands. Since the density of the acid is greater than the density of water, then when the acid is poured into the water in a thin stream, the acid immediately sinks to the bottom and no liquid is sprayed

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