The intermolecular interaction that is dependent on the inverse cube of distance between the molecules is:

$o-$nitrophenol can be easily steam distilled whereas $p-$nitrophenol cannot be. This is because of

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Dipole-dipole interactions are the only non-covalent interactions resulting in hydrogen bond formation.
Reason $R$: Fluorine is the most electronegative element and hydrogen bonds in $HF$ are symmetrical.

Correct decreasing order of boiling point of given compounds:
$I. \ HCl$
$II. \ H_2O$
$III. \ HF$
$IV. \ NH_3$

Which of the following hydrogen bonds is the strongest in the vapour phase?

Which of the following compounds shows evidence of the strongest hydrogen bonding?