Question

22. Vish went to an electrical shop along with her father to purchase a bulb and some electrical equipment. After returning home, Vish looking at the bulb keenly asked her father. Is it filled with air or vacuum? Her father told her that it was filled with nitrogen or argon. She asked him why the bulb could not be filled with air which is readily available, as nitrogen is obviously a part of air? What was her father's correct explanation to her question?

Answer 1

• Air is a homogeneous mixture of gases that also contains argon $\left(\mathrm{Ar}\right)$ and nitrogen $\left({\mathrm{N}}_2\right)$ which are used for filling electric bulbs.
• Air that is readily available could not be filled in electric bulbs because air contains oxygen $\left({\mathrm{O}}_2\right)$ which oxidizes the filament of the bulb and reduces the life of the bulb.
• Whereas argon and nitrogen are chemically unreactive gases so they do not react with the filament of the bulb.