Used primarily in the semiconductor industry for etching silicon wafers due to its ability to dissolve silica and silicates. Commonly applied in glass etching, both for industrial glass processing and decorative purposes. Employed in oil refining as a catalyst in alkylation processes to produce high-octane gasoline. Utilized in metal cleaning and pickling to remove oxides and scale from stainless steel and other alloys. Found in household rust removers and concrete cleaners for its effectiveness in dissolving mineral deposits. Also used in analytical chemistry for sample preparation involving siliceous materials. Requires extreme handling precautions due to high toxicity and deep tissue penetration.