Which gas has a slightly sweet taste and odor?

Nitrous oxide is known for its slightly sweet taste and odor, making it distinctive among the gases listed. This property contributes to its use as an anesthetic in medical applications, where its pleasant scent and flavor can help ease patient anxiety.

The sweet taste and odor can make nitrous oxide more palatable and less intimidating for patients during procedures. It is important in medical settings as it also serves as an analgesic. This unique sensory characteristic is a key reason why nitrous oxide is utilized in environments that require soothing, as it can provide both a calming effect and effective pain relief.

The other gases listed do not possess this sweet taste or odor, which differentiates nitrous oxide in its applications and usage in the medical field.