The correct answer is option 1: in etching glass.

Hydrofluoric acid is commonly used in the process of etching glass. When hydrofluoric acid comes into contact with glass, it reacts with the silicon dioxide present in the glass, resulting in a process called etching. Etching involves the removal of a thin layer of glass, creating a frosted or matte appearance.

Option 2: as a bleaching agent is incorrect. Hydrofluoric acid is not commonly used as a bleaching agent in industries or household applications.

Option 3: as an extremely strong oxidizing agent is incorrect. Hydrofluoric acid is not primarily known for its oxidizing properties. It is mostly used for its corrosive and etching nature.

Option 4: in the preparation of strong organic fluorine compounds is incorrect. While hydrofluoric acid may be used in the preparation of some organic fluorine compounds, it is not the principal use of hydrofluoric acid.