Question

how can you prove that water vapour is released during exhalation​

Answer 1

Rapid diffusion of water (evaporation) occurs from the fluid lining the surfaces of the airways (e.g., bronchi), the airspaces (e.g., alveoli), and mouth into the expiratory flow. Exhaled water vapor remains in the gas phase until it is cooled and captured as droplets in the condenser.