NITROGEN OBTAINED FROM THE LIQUEFACTION OF AIR HAS A HIGHER DENSITY THAN THAT OBTAINED FROM NITROGEN CONTAINING COMPOUNDS BECAUSE THE FORMER CONTAINS

• A. water vapour
• B. oxygen
• C. carbon (IV) oxide
• D. rare gases ✓

Nitrogen obtained from the liquefaction of air has a higher density than that obtained from nitrogen-containing compounds because the former contains rare gases. When nitrogen is obtained through the liquefaction of air, it is separated from other components in the air, including rare gases such as argon, neon, krypton, and xenon. These rare gases have higher atomic masses compared to nitrogen, which increases the overall density of the nitrogen obtained from air liquefaction.

Rare gases are present in very small quantities in the Earth’s atmosphere, with argon being the most abundant among them. When air is liquefied and nitrogen is extracted from it, these rare gases are also collected along with nitrogen. This mixture of gases obtained from air liquefaction has a higher density due to the presence of these heavier rare gases.

In contrast, nitrogen obtained from nitrogen-containing compounds such as ammonia or nitric acid does not contain these rare gases. Instead, it is in the form of pure nitrogen molecules bonded within the compound. As a result, nitrogen obtained from these compounds has a lower density compared to nitrogen obtained from air liquefaction.