This mixture of anions—fluoride, chloride, bromide, and sulfate—finds use in analytical chemistry for qualitative ion testing and separation procedures. The combination allows for systematic identification of cations in solution based on selective precipitation. For instance, chloride ions are commonly used to precipitate silver, lead, and mercury ions, while sulfate helps detect barium, strontium, and calcium. Fluoride is useful in masking certain metal ions during titrations and in etching glassware due to its reactivity with silica. Bromide can serve as an alternative to chloride in specific precipitation tests and in the synthesis of organic bromides. Together, these anions support comprehensive wet-chemistry schemes in environmental testing, water quality analysis, and educational laboratory work where stepwise ion detection is required.