Which of the following is used for writing on glass ?

Hydrogen fluoride (HF), typically in its aqueous form as hydrofluoric acid, is the primary chemical used for writing on or etching glass. Glass is predominantly composed of silicon dioxide (SiO2), which is chemically stable and resistant to most acids [t1, t3]. However, hydrofluoric acid has a unique ability to react with silicon dioxide to form soluble silicon tetrafluoride (SiF4) or hexafluorosilicic acid (H2SiF6) [t1, t4]. This chemical reaction breaks the silicon-oxygen bonds, effectively dissolving a thin layer of the glass surface to create frosted patterns, intricate designs, or permanent markings [t1, t7]. While other substances like graphite can mark glass superficially, they do not etch the surface. Hydrogen fluoride is essential for permanent glass etching and industrial surface treatments due to this specific reactivity [t5, t7].

Sources

1. [1] https://www.sciencedirect.com/science/article/abs/pii/S2214785321077865