Question

Which of the following exhibits the weakest inter-molecular forces?

• A. $N{H}_3$
• B. $HCl$
• C. $He$
• D. $H_{2}O$

Answer 1

The correct option is C $He$

$H_{2}O$ and $N{H}_3$ have hydrogen bonding.
As HCl is a polar molecule, so it has dipole-dipole attraction.
$He$ possess weak London dispersion forces.
H-bonding and dipole-dipole attraction are significantly more stronger than london force. Hence, london dispersion forces are the weakest.