Which of the following compounds is an example of hypnotic drug?

The question asks which compound is an example of a hypnotic drug. Hypnotic drugs are substances that induce sleep and are used to treat insomnia. They typically depress the central nervous system.

Now, let's examine each option:

Option A: Seldane. Seldane is the brand name for terfenadine, an antihistamine used to treat allergies. It is not classified as a hypnotic drug because its primary action is to block histamine receptors, and it was marketed as a non-drowsy antihistamine. Therefore, it does not fit the category.

Option B: Amytal. Amytal is the brand name for amobarbital, which belongs to the barbiturate class of drugs. Barbiturates are central nervous system depressants that act as sedatives and hypnotics. They were historically used to induce sleep in patients with insomnia. Thus, Amytal is a clear example of a hypnotic drug.

Option C: Aspartame. Aspartame is an artificial sweetener used in food and beverages. It is a methyl ester of the dipeptide of aspartic acid and phenylalanine and has no pharmacological effect as a sleep-inducing agent. It is not a drug and certainly not a hypnotic.

Option D: Prontosil. Prontosil is an antibacterial drug, specifically the first sulfonamide antibiotic discovered. It was used to treat bacterial infections by inhibiting bacterial growth and has no sedative or sleep-inducing properties. Hence, it is not a hypnotic drug.

Based on this analysis, only Amytal (Option B) is a hypnotic drug. The correct answer corresponds to option number 2 in the list.

Hence, the correct answer is Option B.