Arrange the bonds in order of increasing ionic character in the molecules. $\mathrm{LiF}$, $\mathrm{K}_2 \mathrm{O}, \mathrm{N}_2, \mathrm{SO}_2$ and $\mathrm{ClF}_3$ :
$\mathrm{N}_2<\mathrm{SO}_2<\mathrm{ClF}_3<\mathrm{K}_2 \mathrm{O}<\mathrm{LiF}$
$\mathrm{ClF}_3<\mathrm{N}_2<\mathrm{SO}_2<\mathrm{K}_2 \mathrm{O}<\mathrm{LiF}$
$\mathrm{LiF}<\mathrm{K}_2 \mathrm{O}<\mathrm{ClF}_3<\mathrm{SO}_2<\mathrm{N}_2$
$\mathrm{N}_2<\mathrm{ClF}_3<\mathrm{SO}_2<\mathrm{K}_2 \mathrm{O}<\mathrm{LiF}$
