Question

Question #e5491

Answer 1

An acid.

Explanation:

It is an acid if it is dissolved in water. It can be found as dissolved in water. It exists as a colorless gas or as a fuming liquid.

Too much fluoride causes health problems, too little of it also causes some health problems. That is why some waters are fluoridated.

Answer 2

`HF` is a compound made up from hydrogen and fluorine.

Explanation:

Fluorine is the most electronegative element, so it adheres strongly to the hydrogen atom. It is a strong dipole.
This is the reason why HF is a weak acid, i.e. is does not completely dissociate in water:

`HF+H_2OrightleftharpoonsH_3O^+ +F^-`

While the other hydrogen halides are strong acids, e.g. HCl:
`HCl+H_2O->H_3O^+ +Cl^-`

Of course if we take away either one of the ions, the equilibrium will shift to the right.