What is purging? why mostly purging with nitrogen is preffered? and how purging is done in industries?

Purging is the displacement of air (Oxygen) and moisture from a by bubbling nitrogen gas into the solvent. nitrogen is preferred because it is chemically inert and it is cheap when compared with other inert gases like helium or neon. In industries, purging is important because it will prevent explosions, eliminate undesired reactions, keep moisture away from products and ensure safety during maintenance.