Sulfuric acid or sulphuric acid, known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, and hydrogen, with the molecular formula H2SO4. It is a colorless, odorless, and viscous liquid that is miscible with water.
Sulfuric acid
Drops of concentrated sulfuric acid rapidly decompose a piece of cotton towel by dehydration.
Rio Tinto with its highly acidic water
Domestic acidic drain cleaners usually contain sulfuric acid at a high concentration which turns a piece of pH paper red and chars it instantly, demonstrating both the strong acidic nature and dehydrating property.
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance's molecules, adsorbing substances can become physically changed, e.g. changing in volume, boiling point, viscosity or some other physical characteristic or property of the substance. For example, a finely dispersed hygroscopic powder, such as a salt, may become clumpy over time due to collection of moisture from the surrounding environment.
Air plant (Tillandsia bulbosa)
The aquatic file snake (A. granulatus) with hygroscopic skin, shown out of water
An orb-weaver spider (Larinioides cornutus) with hygroscopic coated capture threads
Waxy monkey tree frog (Phyllomedusa sauvagii)
