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 compound depends on, among other things, the extent of hydrogen bonding. On this basis explain which of the above two compounds will show higher melting point?
c) Solubility of compounds in water depends on powers to form hydrogen bonds with water. Which of the above compounds will form hydrogen bond with easily and be more stable in it?

Answer

a

Explanation

a) Compound (i) will form intramolecular H-bonding. Intramolecular H-bonding is formed when H-atom. In between the two highly electronegative atoms is present within the same molecule. In ortho-nitrophenol (compound I). H-atom is in between the two oxygen atoms.

Compound (II) forms intermolecular H-bonding. In para-nitrophenol (II) there is a gap between `NO_(2)` and OH group. So, H-bond exists between H-atoms of one molecule and O-atom of another molecules as depicted below.

b) Compound (II) will have higher melting point because large number of molecules and joined together by H-bonds.
c) Due to intramolecular H-bonding, compound (I) is not able to form H-bond with water, so it is lesss soluble in water. While molecules of compound II form H-bonding with `H_(2)O` easily. so it is soluble in water.