Nitrogen is the gas richest in air.
The Composition of Air
Air is a mixture of several gases. The most abundant gas in the Earth's atmosphere is nitrogen (N₂), comprising approximately 78% of its volume. Oxygen (O₂) follows at around 21%, while other gases, including argon (Ar), carbon dioxide (CO₂), and trace amounts of others, make up the remaining percentage. The provided reference states that nitrogen makes up about 78% of air, oxygen is about 21%, and argon constitutes about 0.93%. This clearly shows nitrogen's dominance.
Many references discuss "rich" in the context of fuel-air mixtures in engines. A rich mixture means there is more fuel than air, leading to incomplete combustion. This is different from the question's context, which asks about the composition of air itself.
Therefore, focusing on the atmospheric composition, the answer remains consistent: Nitrogen is the gas present in the highest concentration within air.
