Sodium sulfite is a chemical compound that is commonly used as a preservative in the food industry. It can also be used in photography to prevent oxidation of developer solutions. However, there are a number of synonyms that can be used to refer to this compound. Some of the most commonly used synonyms include sodium sulphite, sodium sulfite anhydrous, and sodium sulfur dioxide. These names all refer to the same compound, which is the sodium salt of sulfurous acid. Regardless of which name is used, it always refers to a white crystalline powder that is soluble in water and has a slightly sulfurous odor.