Brine is an aqueous solution of

Brine is fundamentally defined as a high-concentration aqueous solution of sodium chloride (NaCl). In industrial chemistry, particularly the chlor-alkali industry, brine serves as the primary feedstock for producing chemicals like chlorine and sodium hydroxide through electrolysis [1]. While the term can occasionally refer to other salt solutions in specific geological or industrial contexts, such as coal seam gas brine containing bicarbonates [2], its standard definition in general science and common industrial applications refers to salt water where NaCl is the predominant component. Sodium chloride, commonly known as table salt, dissociates into Na+ and Cl- ions in water, creating an electrically conductive solution [3]. This solution typically exceeds the salinity of seawater, often reaching near-saturation levels of approximately 26% NaCl by weight. Therefore, brine is most accurately identified as an aqueous solution of NaCl.

Sources

1. [1] https://www1.eere.energy.gov/manufacturing/resources/chemicals/pdfs/profile_chap6.pdf
2. [2] https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-Chloride
3. [3] https://www.sciencedirect.com/science/article/abs/pii/S138358661400121X