Which of the following substances is known for the alkalization of urine?

The substance known for the alkalization of urine is barbiturate. Barbiturates can influence the body’s acid-base balance, leading to the alteration of urine pH. When barbiturates are metabolized, they can have a systemic effect that results in the urine becoming more alkaline. This property makes them significant in contexts like pharmacology and toxicology, particularly when considering how drugs can change the excretion profiles of other substances in the urine.

Other substances listed, such as chlorpropamide (a sulfonylurea), NSAIDs (non-steroidal anti-inflammatory drugs), and sulfonamides (an antibiotic), do not have a direct or prominent role in urinary alkalization. Chlorpropamide is primarily used for managing diabetes and has different metabolic pathways. NSAIDs are used primarily for pain relief and inflammation but do not significantly alter urine pH. Similarly, sulfonamides are often involved in antibiotic action rather than affecting urine pH notably.

Thus, the characteristic of barbiturates leading to the alkalization of urine makes them the correct choice in this context.