Concentrated nitric acid is corrosive, which is the protein degeneration of skin, and concentrated sulfuric acid is the dehydration and carbonization of skin. Obviously, concentrated sulfuric acid is more powerful. In addition, concentrated nitric acid is a fuming liquid with a pungent smell, which is easily smelled by people who splash nitric acid. Concentrated sulfuric acid has no taste.

Phosphorus pentoxide is solid, and its contact area with human body is relatively small, so the harm is of course relatively small.

In addition, concentrated sulfuric acid is also superior to nitric acid and phosphorus pentoxide.

Fumigating sulfuric acid is of little use and difficult to buy. Concentrated sulfuric acid is enough. Fumigating sulfuric acid is not fatal!