Final answer:
Death from hydrogen sulfide poisoning can be immediate with high concentration exposure, as it rapidly leads to unconsciousness and respiratory failure.
Step-by-step explanation:
The speed at which death occurs from hydrogen sulfide poisoning varies depending on the concentration and duration of exposure. In case of high concentration exposure, death can be immediate. As hydrogen sulfide is a gas, the rate at which it enters the body and affects vital biological processes is related to its effusion rate, which is much faster than that of oxygen. Typically, hydrogen sulfide poisoning leads to rapid unconsciousness and respiratory failure, potentially resulting in death within minutes.