Which condition would most likely produce acidic urine due to dehydration?

• A. Urinary tract infection with urease-producing bacteria
• B. Dehydration
• C. Chronic kidney disease
• D. High fluid intake

Answer: (B)

When urine becomes acidic, it’s often because the body is trying to conserve water and maintain acid–base balance under stress, such as dehydration. Dehydration signals the kidneys to conserve water, concentrating the urine. In this state, hydrogen ions are actively secreted into the urine by the distal nephron, and aldosterone-driven H+ secretion increases. This combination lowers the urine’s pH, making it more acidic.

So, the condition described—dehydration—directly leads to more concentrated urine with increased acid excretion, producing an acidic urine sample.

The other scenarios don’t fit as well: a urinary tract infection with urease-producing bacteria raises urine pH (it makes urine more alkaline) because ammonia is produced from urea. Chronic kidney disease often disrupts acid–base balance and can blunt acid excretion, not reliably producing acidic urine from dehydration. Very high fluid intake dilutes urine, usually making it less acidic or neutral rather than more acidic.