Hydrofluoric acid is aqueous hydrogen fluoride (dissolved in water). Hydrogen fluoride will form hydrofluoric acid when it comes in contact with water.
After another 5730 years ( three half lives or 17190 years) 17.5 /2 = 8.75mg decays and 8.75g remains left. after three half lives or 17190 years, 8.75 g of C-14 will be
