In a lab experiment finding the limiting reactant with Sodium bicarbonate and ci

Question

In a lab experiment finding the limiting reactant with Sodium bicarbonate and citric acid, it was found that the limiting reactant was sodium bicarbonate. If I have to devise an experiment to test my conclusion to which reactant is limiting do I add sodium bicarbonate or citric acid?

I added more sodium bicarbonate and it began to react and fizz again, does this prove that citric acid is in excess?

Part two I had to make a mixture that citric acid was the limiting reactant.

I did not have time to finish the lab   -- What experiment would I devise to test my conclusion to that citric acid was limited.   Would I add citric acid? what would happen?

Explanation / Answer

H3C6H5O7(aq) + 3NaHCO3(aq) -----> 3CO2(g) + 3H2O(l) + Na3C6H5O7(aq)

If CO2 as the major product from citric acid and sodium bicarbonate.

1 mole of citric acid gives 3 moles of CO2 and 3 moles of sodium bicarbonate gives 3 moles of CO2.

If you use 5 g of citric acid and 10 g of sodium bicarbonate.moles of citric acid = 5/192 = 0.026 and moles of sodium bicarbonate = 10/84 = 0.12 moles.

1 mole citric acid gives ------ 3 moles of CO2

0.026 moles of citric acid gives ------ 3 X 0.026 = 0.078 moles of CO2

3 moles of sodium bicarbonate gives ------ 3 moles of CO2

0.12 moles of sodium bicarbonate gives ---- (3 X 0.12) / 3 = 0.12 moles of CO2

from the above analysis we can say Citric acid is the limiting reagent.

limiting reagent: The reactant which is completely used up in the chemical reaction. or the reactant which controles the formation of product in a chemical reaction.

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