What happens to water if:

(a) it is kept in a deep freezer?

(b) it is heated?

Explain the change of state of water for the above two conditions with the help of kinetic theory.

(a) When water is kept in a deep freezer, it gets cooled and changes into ice at 0°C.

Water $\xrightarrow[\text{freeze}]{\text{deep}}$ ice (0°C)

Phenomenon of change of state of water — When water is kept in deep freezer, it changes into ice at 0°C. This is because when cooling is done, the kinetic energy decreases. Thus, the spaces between the particles decrease and the forces of attraction increase. This also affects the movements of particles, and at 0°C water starts converting into its solid state, i.e. ice.

(b) When water is heated it changes into steam at 100°C.

Water $\xrightarrow{\text{heating}}$ steam (100°C)

Phenomenon of change of state of water — On heating water, it changes into steam at 100°C. When heat is provided to water, its constituent particles gain more kinetic energy and start moving even more vigorously. The forces of attraction become almost negligible, increasing the intermolecular spaces and ultimately water changes into steam at 100°C.