You have three substances: #"lithium fluoride"#; #"carbon dioxide"#; and #"dinitrogen pentoxide"#. Which species should have the highest melting and boiling point?

1 Answer
Feb 23, 2017

Answer:

You have 3 substances. One is ionic; and the other two are molecular..........

Explanation:

Ionic substances are intrinsically non-molecular, and (usually) exhibit exceptionally high melting and boiling points. And thus #"lithium fluoride"#, #i.e. Li^(+)F^-#, an ionic substance, with no discrete molecules, should have much higher melting and boiling points than MOLECULAR #CO_2#, and #N_2O_5#.

But, as I have said here before, you are a physical scientist. You are required to interpret data, not to remember them. Look up the melting points/boiling points of the three substances, and see if you can interpret the data on the basis of molecularity.