Answer:

Explanation:
Given:
A solution contains one or more of the following ions such as Ag,
and 
Here the Lithium bromide is added to the solution and no precipitate forms
Solution:
Since with LiBr no precipitation takes place therefore Ag+ is absent
Here on adding
to it precipitation takes place.
Precipitate is as follows,

Thus,
is present
When
is added again precipitation takes place.
Therefore the reaction is as follows,

Therefore,
are present in the solution
Answer:
Polarizing power refers to an atoms ability to pull an electron toward it, polarizing the atom the electron comes from. Since cations are positive, they are able to attract electrons toward themselves. Anions are negative and so do not attract more electrons.
Therefore, Be2+ has a higher polarizing power because it has a higher quantitiy of protons, hence a higher polarizing power.
How strong the bonds are between the atoms