41. The second main catalyst option is hydrofluoric acid . 42. Hydrofluoric acid is also the strongest of the hydrohalic acids in acetic acid and similar solvents.43. Counterintuitively, perhaps, what makes hydrofluoric acid so deadly is not that it is a strong acid. 44. Skin contact with hydrogen fluoride will cause an immediate reaction with water which produces hydrofluoric acid . 45. _Fluorosilicic or hydrofluoric acid , used to fluoridate water. 46. Diluted hydrofluoric acid can be brushed onto the plate to create areas of very delicate tone. 47. In addition to being a highly corrosive liquid, hydrofluoric acid is also a powerful contact poison. 48. Ingested fluoride forms hydrofluoric acid in the stomach. 49. The hydrates crystallize from aqueous hydrofluoric acid . 50. In 1996, Michael Hanly, a garbage collector, unknowingly came across hydrofluoric acid tossed out with the trash.
