What is the approximate percentage of nitrogen in dry air?

What is the approximate percentage of nitrogen in dry air?

• A. 78%
• B. 20.93%
• C. 0.03%
• D. 79%

Answer: (D)

Nitrogen is the most abundant component of dry air, making up about four-fifths of its composition. In practice, the commonly cited approximate value is around 79%. The rest is mainly oxygen, close to 21%, with small amounts of other gases. Saying nitrogen is about 79% reflects its dominance in dry air, and that figure is the standard approximation used in many texts. The other numbers correspond to other parts of the air mix or tighter values (for example, oxygen is about 20.93%, carbon dioxide is around 0.04%), but they don’t describe nitrogen’s share as clearly in the dry-air context.

Nitrogen is the most abundant component of dry air, making up about four-fifths of its composition. In practice, the commonly cited approximate value is around 79%. The rest is mainly oxygen, close to 21%, with small amounts of other gases. Saying nitrogen is about 79% reflects its dominance in dry air, and that figure is the standard approximation used in many texts. The other numbers correspond to other parts of the air mix or tighter values (for example, oxygen is about 20.93%, carbon dioxide is around 0.04%), but they don’t describe nitrogen’s share as clearly in the dry-air context.