In which compound is the hydrogen bonding the strongest in its liquid phase?

$H_2O$ is a liquid while $H_2S$ is a gas due to:

How many water molecules present in $CuSO_4 \cdot 5 H_2 O$ are hydrogen bonded?

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

Ortho-nitrophenol is less soluble in water than $p-$ and $m-$nitrophenol because...

The steam volatile compounds among the following are $:$
$(A)$ $o$-nitrophenol
$(B)$ $o$-nitroaniline
$(C)$ $p$-aminophenol
$(D)$ $p$-hydroquinone
Choose the correct answer from the options given below $:$