Chem簡單MC問題一條

carbon is in giant covalent structure
NaClis in ionic structure
and the other two is actually in simple molecular structure
of course, simple molecular structure will have the least boiling point ga la!

However, for simple molecular structure, the intermolecular force between molecules will be can der Waal's force, in the two answers given. The strength of van der Waal's force is determined by the no. of electron in the molecule.(I am not sure which form are u in..if u are in F.6...you should know this,but if u are in F.4, just take it as a fact in your level.) As C2H6 has more electron and have a greater molecular size, its van der Waals' force is stronger than CH4 thus the answer should be D.

As the wiki data listed from the above answer
you can see clearly C should have the highest boiling point
if it exists as a diamond.
As covalent bond in giant structure needs lots of energy to break it down
the boiling pt is very very high!

The answer is D methane...

Because carbon(boiling point:3727 °C) and sodium chloride(boiling point:1465 °C) have higher boiling point,and the boiling point of ethane is -88.6°C but the boiling point of methane is -161.6°C .Because methane have the lowest boiling point,so the answer is D.