Which of the following compounds volatilises on heating?

Amongst $LiCl$,$RbCl$,$BeCl_2$,and $MgCl_2$,the compounds with the greatest and the least ionic character,respectively,are:

Given below are two statements:
Statement $I$: The correct order in terms of bond dissociation enthalpy is $Cl_{2} > Br_{2} > F_{2} > I_{2}$.
Statement $II$: The correct trend in the covalent character of the metal halides is $[SnCl_{4} > SnCl_{2}]$, $[PbCl_{4} > PbCl_{2}]$ and $[UF_{4} > UF_{6}]$.
In the light of the above statements, choose the correct answer from the options given below:

How does the covalent character vary in $LiCl, BeCl_2, BCl_3$ and $CCl_4$?

Polarization is the distortion of the shape of an anion by an adjacently placed cation. Which of the following statements is correct?

Which of the following is helpful in the formation of an ionic bond?