1. Consider melting of ice in a closed container at 273 K. This system reach a state of physical equilibrium in which the amount of water in the solid phase and liquid phase does not change with time.
2. In this process. the total number of water molecules leaving from and returning to the solid phase at any instant are equal.
3. If some ice cubes and water are placed in a thermos flask (at 273K and 1 atm) then there will be no change in the mass of ice and water.
4. At equilibrium: Rate of melting of ice Rate of freezing of water H2O(l) ⇌ H2O(g)
