Answer:
Because it's not soluble in water, need to be heated acidic solution
Step-by-step explanation:
Calcium Fluoride Formula: CaF2 Comprises of Ca2+ and F−
H2O = Water H+ O2- OH-
Insoluble in water
In order to dissolve a salt, you have to break apart the ions and hydrate them via a solvent.
Need to read
HSAB concept( Pearson acid-base concept) is an initialism for "hard and soft (Lewis) acids and bases"
So F- is a Halogen which is a Hard Base
And OH- is a Hard base as well
And H- is a soft base
So soft acids react best with soft bases and hard acids react best with hard bases.
Bases don't react with other bases.