Used primarily in the semiconductor industry for etching silicon wafers due to its ability to dissolve glass and silicon compounds. Widely applied in petroleum refining to catalyze alkylation processes for high-octane fuel production. Employed in metal cleaning and pickling to remove oxides and scale from stainless steel and other alloys. Common in glass frosting and etching for decorative purposes in windows and mirrors. Utilized in the production of fluorocarbons and refrigerants. Also found in some household rust removers and concrete cleaners, though handling requires extreme caution due to high toxicity and corrosivity, especially its ability to penetrate tissue and decalcify bone.