Ans. is 'c' i.e., Paradoxical aciduria with hyponatremia and hypochloremia Persistent vomiting leads to loss of large amount of gastric fluid. o Gastric fluid consists of large amount of HC1. o Thus in pyloric stenosis, repeated vomiting causes hypochloremic metabolic alkalosis. o In early stages the kidneys are able to compensate by reabsorbing hydrogen and chloride ions in exchange for sodium, potassium and bicarbonate, however as the body stores of sodium and potassium becomes depleted, these ions are selectively retained while hydrogen is excreted in urine, causing the paradoxical aciduria. o This aggravates the alkalotic stage.