Its just Calcium Flouride because as you can see it is an Ionic bond (Ca is metal and fl is a gas usually)
1) 
The capacitance of a parallel-plate capacitor is given by:

where
is the vacuum permittivity
A is the area of each plate
d is the distance between the plates
Here, the radius of each plate is

so the area is

While the separation between the plates is

So the capacitance is

And now we can find the energy stored,which is given by:

2) 0.71 J/m^3
The magnitude of the electric field is given by

and the energy density of the electric field is given by

and using
, we find

LiCl, because lithium (Li) has one positively charged ion (1+), and
chloride (Cl) has one negatively charged ion (1-), so they
cancel each other out.
Answer:
The speed of light is that medium is 281907786.2 m/s.
Explanation:
since the critical angle is Фc = 430, we know that the refractive index is given by:
n = 1/sin(Фc)
= 1/sin(430)
= 1.06
then if n is the refractive index of the medium and c is the speed of light, then the speed of light in the medium is given by:
v = c/n
= (3×10^8)/(1.06)
= 281907786.2 m/s
Therefore, the speed of light is that medium is 281907786.2 m/s.