# Sodium fluoride and varying pH - HF risk [closed]

I'm looking into conducting an experiment on the adsorption of fluoride (for my International Baccalaureate Extended Essay). As I will be investigating the role of $\mathrm{pH}$ in adsorption capacity, I will be dealing with $\ce{NaF}$ solutions of varying $\mathrm{pH}$. Could hydrofluoric acid be created by this process, and could it be dangerous in the dilute concentrations I am dealing with (<$0.5\ \mathrm{g\ L^{-1}}$)?

My reasoning is that added $\ce{H+}$ will move the equilibrium of the buffer $\ce{F^{−}(aq) +H3O+(aq) <=> HF(aq) + H2O(l)}$ to the right, and the $\mathrm{pH}$ will hardly change until the buffer capacity is exceeded. I'm still not sure whether this poses a health risk, though.

• May 26, 2016 at 21:36
• (Soluble) fluorides are always poisonous, only the undissociated, relatively non-polar HF (i.e. fluorides under acidic conditions) quickly penetrates the skin.
– Karl
May 27, 2016 at 11:49