Answer to Question #55719 in General Chemistry for tracy guido

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?
Thank you

Answer 1

1) To verify conclusion that the limiting reactant is Sodium bicarbonate you should add opposite reactant (in this case citric acid) and check for the signs of reaction (in this case “fizzing”). In addition, pH check would be effective here.
2) If you added more sodium bicarbonate and got more gas, then there is still some acid. So, acid in excess.
3) You always have to add opposite reactant, not the same. Therefore, to test if there is still some acid, you need to add bicarbonate and check for fizzing. If you add more acid to the already excess of acid you`d get no reaction.