Which among the following is least covalent in nature?

Which of the following order is incorrect?

The correct order of covalent bond character of $BCl_3, CCl_4, BeCl_2, LiCl$ is

The charge/size ratio of a cation determines its polarizing power. Which of the following sequences represents the increasing order of the polarizing power of the cations $K^+$,$Ca^{2+}$,$Mg^{2+}$,and $Be^{2+}$?

Which of the following orders is incorrect?

How many of the following orders of covalent character are $TRUE$?
$(i)$ $LiF < LiCl < LiBr < LiI$ (Fajans' rule: covalent character increases with increasing size of anion)
$(ii)$ $CaCl_2 < FeCl_2 < FeCl_3$ (Fajans' rule: covalent character increases with increasing charge on cation)
$(iii)$ $Hg_2Cl_2 < HgCl_2$ (Fajans' rule: covalent character increases with increasing charge on cation)
$(iv)$ $ZnCl_2 < CdCl_2 < HgCl_2$ (Fajans' rule: covalent character increases with increasing polarizability of cation)
$(v)$ $CuCl < AgCl < AuCl$ (Fajans' rule: covalent character increases with increasing polarizability of cation)
$(vi)$ $AlN > Al_2O_3 > AlF_3$ (Fajans' rule: covalent character increases with increasing charge on anion)
$(vii)$ $CaF_2 < CaCl_2 < CaBr_2 < CaI_2$ (Fajans' rule: covalent character increases with increasing size of anion)