Hydrogen Bonding

Step 1: Enthalpy of physiolysis.
The enthalpy of physiolysis refers to the energy required to break bonds in a molecule. has the highest bond dissociation energy among the given molecules.
Thus, the correct answer is (3).

Step 1: Hydrogen bonding.
The high boiling point of water is due to the strong hydrogen bonds between the water molecules, which requires a large amount of energy to break.
Thus, the correct answer is (3).

The reactions of zinc with sulphuric acid and excess of sodium hydroxide separately are given below:


In both the reactions, mole of is evolved.
Hence, the ratio of volumes of hydrogen evolved is .

Step 1: NH has covalent bonds.
Step 2: One N–H bond is coordinate.
Step 3: As an ion, it forms electrovalent bonds in salts.

NH₄⁺ contains: • Covalent bonds (N–H), • One coordinate bond (from N to H⁺), • Electrovalent bond between NH₄⁺ and counter ion.

Step 1: {Intramolecular Hydrogen Bonding}
In o-nitrophenol, the hydrogen of the group and the oxygen of the nitro group form intramolecular hydrogen bonding producing a six-membered ring structure. In m-nitrophenol, p-nitrophenol, and phenol, intermolecular hydrogen bonding is present. Hence, the correct answer is (A).