When a salt loses its water of crystallization to the atmosphere on exposure, the process is said to be

The correct term is "Efflorescence". Efflorescence is a process where a salt loses its water of crystallization to the atmosphere, causing the salt crystals to dissolve and eventually evaporate, leaving behind a white powdery residue on the surface. This can happen due to changes in temperature, humidity, or air movement. Some examples of salts that can effloresce include sodium carbonate, calcium sulfate, and magnesium chloride. It's important to note that efflorescence is different from the other three options you listed: - Deliquescence refers to a substance that absorbs moisture from the air until it dissolves in the absorbed water. - Effervescence is the release of gas (typically carbon dioxide) from a substance, often in the form of bubbles. - Fluorescence is the property of certain substances to emit light (typically in the ultraviolet or visible spectrum) after absorbing light or other electromagnetic radiation.