A solid is hard and the molecules are packed together, a liquid can move around freely because the molecules aren't as packed together :)
Answer:
the ionic radius of the anion 
Explanation:
From the diagram shown below :
The anion
is located at the corners
The cation
is located at the body center
The Body diagonal length = 
∴ 
Given that :
(i.e the ratio of the ionic radius of the cation to the ionic radius of
the anion )

Also ; a = 664 pm
Then :

Therefore, the ionic radius of the anion 
Based off the salt levels in each water.
The answer is 0.25 M
Use the equation C1V1=C2V2
(.5)(100)=x(200)
x=0.25