In renal failure, metabolic acidosis is due to?

Metabolic acidosis can occur because of increased endogenous acid production (lactate and ketoacids) loss of bicarbonate accumulation of endogenous acid (as seen in renal failure) -Ammonia is excreted out linked to H+ as ammonium ion and for every positive charge lost, chloride is lost to maintain electroneutrality. -In case of a renal failure both ammonia and protons are retained leading to high anion gap acidosis as the positive charges in the body are increased.