Question: how many moles of carbon dioxide are produced by the complete oxidation of 1 mole of pyruvate?
Answer: Each puruvate produces acetyl CoA molecule and releases carbon dioxide. Also, Kreb's cycle produces 2 carbon dioxide molecules during formation of alpha-ketoglutaric acid and succinic acid respectively. Hence, total 3 carbon dioxide molecules are produced from pyruvate by Kreb's cycle.