Final answer:
Hydrogen sulfide (H₂S) emits an odor similar to rotten eggs and is exceptionally toxic, necessitating careful handling. The correct answer is option A.
Step-by-step explanation:
Hydrogen sulfide (H₂S) is known for its characteristic smell of rotten eggs. It is a colorless gas that is often associated with the odor found in hot springs and can be very toxic. In fact, exposure to hydrogen sulfide can paralyze the olfactory nerves, inhibiting the sense of smell, which makes it particularly deceptive and hazardous.
Therefore, handling hydrogen sulfide requires great care due to its high toxicity. As a weak diprotic acid, H₂S forms hydrosulfuric acid when dissolved in water and it can cause aqueous solutions of soluble sulfides and hydrogen sulfides to become basic. With this in mind, the correct answer to what hydrogen sulfide smells like is A. Rotten Eggs.