Select the compound from the following which dissolves in water.

Structures of molecules of two compounds are given below:
$(a)$ Which of the two compounds will have intermolecular hydrogen bonding and which compound is expected to show intramolecular hydrogen bonding.
$(b)$ The melting point of a compound depends on,among other things,the extent of hydrogen bonding. On this basis,explain which of the above two compounds will show a higher melting point.
$(c)$ Solubility of compounds in water depends on the power to form hydrogen bonds with water. Which of the above compounds will form hydrogen bonds with water easily and be more soluble in it?

Orthophosphoric acid $(H_3PO_4)$ exhibits high viscosity due to:

Would you expect the hydrides of $N$,$O$ and $F$ to have lower boiling points than the hydrides of their subsequent group members? Give reasons.

The relatively high boiling point of $HF$ is due to:

In which of the following is intermolecular $H$-bonding present?