<prompt> Most common biochemical abnormality in congenital pyloric stenosis.Hyperkalemic metabolic acidosisHypokalemic metabolic acidosisHyperkalemic metabolic alkalosisHypokalemic metabolic alkalosis  <response>: Ans. is d i.e. Hypokalemic metabolic alkalosis Repeated vomiting leads to hypochloremic, hypokalemic metabolic alkalosis. The urine is alkaline initially but eventually it becomes acidic paradoxical aciduria 