Which gas is commonly known to be slightly sweet in taste?

Nitrous oxide (N2O) is known to have a slightly sweet taste, which is one of its distinguishing sensory characteristics. This property makes N2O particularly unique among the gases listed. It is often used in medical settings for its analgesic and anesthetic properties, and its sweet flavor can be noticeable when inhaled.

In contrast, oxygen is tasteless and odorless, carbon dioxide has a slightly sour or acidic taste, and helium is also tasteless and odorless. This sensory distinction emphasizes the unique properties of nitrous oxide in both medical applications and its sensory profile. Understanding these characteristics is essential for those working with these gases in medical settings.