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

The substance known for the alkalization of urine is barbiturate. Barbiturates are a class of drugs that have the capacity to increase the pH of urine, making it more alkaline. This occurs because barbiturates can cause the kidneys to retain bicarbonate, which leads to higher urine pH levels. The alkalization of urine is significant in various medical and forensic contexts, such as influencing the excretion of certain drugs and toxins.

In contrast, chlorpropamide is primarily an oral hypoglycemic agent used for managing diabetes and does not have a noted effect on urine alkalization. Nonsteroidal anti-inflammatory drugs (NSAIDs) also generally do not affect urine pH in a clinically significant manner. Sulfonamides are a group of antibiotics that can create an acidic environment in urine, which may lead to crystallization and potentially harmful kidney effects, rather than alkalization.