Q. Assertion : When ice and water are kept in a perfectly insulated thermos flask at and the atmospheric pressure, there is no change in mass of ice and water.
Reason : The system is in static equilibrium.

 1982  186 Equilibrium Report Error

Solution:

There is no change in mass of ice and water, as rates of transfer of molecules from ice into water and of reverse transfer from water into ice are equal at atmospheric pressure and . The system is in dynamic equilibrium.