What phenomenon occurs when the dissolved salts are deposited on a material's surface due to evaporation?

The phenomenon where dissolved salts are deposited on a material's surface due to evaporation is known as efflorescence. When water evaporates from a surface, particularly in porous materials like concrete or brick, it can carry dissolved salts with it. As the water evaporates, these salts are left behind, forming a white, powdery residue on the surface. This process is often seen in basements or on walls where moisture is present, and it can indicate underlying moisture issues.

Mildew, fungal growth, and surface corrosion involve biological or chemical processes that differ significantly from the simple deposition of salts. Mildew and fungal growth are biotic problems associated with moisture and organic materials, while surface corrosion refers to the degradation of materials, typically metals, due to chemical reactions with the environment, not just the deposition of salts. Understanding efflorescence is essential for assessing moisture conditions in buildings and addressing potential water intrusion issues.