Answer: Option (b) is the correct answer.
Explanation:
When a compound contains a strong bond between its combining atoms or molecules then the compound will have a high boiling point.
An ionic bond is a strong bond because it contains strong force of attraction between two oppositely charged atoms.
For example, LiF is an ionic compound in which lithium is [tex]Li^{+}[/tex] ion and fluorine is [tex]F^{-}[/tex] ion.
Therefore, LiF compound will have strong force of attraction.
On the other hand, covalent compounds have weak bond due to sharing of electrons. Hence, they have low boiling point.
For example, [tex]CO_{2}[/tex], [tex]CCl_{4}[/tex], and [tex]H_{2}[/tex] etc are covalent compounds.
Thus, we can conclude that LiF substance has the highest boiling point.
