This is a reversible reaction because you can boil the water to make water vapor and when the water vapor is cooled down, it ill turn back into its original liquid, water. This occurs because of hydrogen bonding between water molecules.
When water is boiled water molecules changed into vapors when these vapors condensed water changed into liquid.
So it is reversible reaction.
Explanation:
Water molecules are connected through the hydrogen bonding. When water is boiled the kinetic energy of water molecules increased and point is reached when kinetic energy is so high and water molecules overcome the external pressure and escape from the surface. Thus water molecules convert into vapors.
In case of cooling process extra energy is released. Vapors becomes cooled and kinetic energy decreased vapors are changed into liquid state.
When water is boiled water molecules changed into vapors when these vapors condensed water changed into liquid.
