[junbumkim]

In general, the boiling point increases in the order of Diatomic Element -> Monatomic Element -> Non Polar Compound ->Polar Compound.

How would you know which has higher boiling point between HCl, and LiF ?

Both are polar. I would assume F is has a smaller radius than Cl so it's higher electron negativity. Thus, LiF would have higher boiling pt. Am I correct?

[lemonoman]

Another things to remember is covalent compounds boil at temperatures MUCH lower than ionic ones do...because of the bonding involved between the molecules.

So keeping in mind that HCl is a liquid at room temperature, and LiF is an ionic solid ... maybe that will help you out

[billnotgatez]

Is not hydrogen Chloride a gas at room temperature?

[lemonoman]

Is not hydrogen Chloride a gas at room temperature?

Oops.  I always just think about the aqueous HCl one sees in labs.  HCl boils at -85 C at STP.