Fluoride is an ion with the formula F- and must be paired with a positive ion (such as sodium or Na+) to form a substance. In the case of the use of fluoride ions in toothpaste and other dental...
One way to make sodium fluoride is to react the hydroxide with hydrofluoric acid. The resulting salt can then be purified by recrystallization. NaOH (aq) + HF (aq) = NaF (aq) + H2O (l) While not a...