Compare uniformitarianism with catastrophism

Achemistry student weighs out of phosphoric acid , a triprotic acid, into a volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with solution. calculate the volume of solution the student will need to add to reach the final equivalence point. round your answer to significant digits.

What reaction is taking place? 02 + c3h8 = h20 + co2

Why does his teacher ask him to balance the equation by including the correct coefficient