The pair likely to form the strongest hydrogen bonding is

Use the information and data given below to answer the questions $(a)$ to $(c)$. Stronger intermolecular forces result in higher boiling point.
Strength of London forces increases with the number of electrons in the molecule.
Boiling points of $HF, HCl, HBr$ and $HI$ are $293 \ K, 189 \ K, 200 \ K$ and $238 \ K$ respectively.
$(a)$ Which type of intermolecular forces are present in the molecules $HF, HCl, HBr$ and $HI$?
$(b)$ Looking at the trend of boiling points of $HCl, HBr$ and $HI$,explain out of dipole-dipole interaction and London interaction,which one is predominant here.
$(c)$ Why is the boiling point of hydrogen fluoride highest while that of hydrogen chloride lowest?

The electronegativity of oxygen is higher than that of sulfur. Yet,$H_2S$ is acidic while $H_2O$ is neutral. The reason for this is .........

In which of the following molecules does hydrogen bonding occur? Why?
$CH_3OH, CH_3COOH, CH_4, Cl, HF, C_6H_6, NH_3, NF_3$

The compound with the highest boiling point is

What type of force is a hydrogen bond?