Which of the following compounds contains a hydrogen bond?

Given below are two statements:
Statement $I$: $o$-Nitrophenol is steam volatile due to intramolecular hydrogen bonding.
Statement $II$: $o$-Nitrophenol has a high melting point due to hydrogen bonding.
In the light of the above statements,choose the most appropriate answer from the options given below:

$o-$Nitrophenol is less soluble in water than $p-$ and $m-$nitrophenols because:

$KF$ combines with $HF$ to form $KHF_2$. Which of the following species are present in this compound?

Select the compound from the following which dissolves in water.

What is the energy of a hydrogen bond?