2 moles of hydrochloric acid was reacted with 4 moles of sodium carbonate. Which reagent is a limiting reagent? Justify your answer with calculations?

2 moles of hydrochloric acid was reacted with 4 moles of sodium carbonate. Which reagent is a limiting reagent? Justify your answer with calculations?

1. First, write out a balanced equation: 2HCl + Na2CO3➡️2NaCl + H2O + CO2
2. Next, from the balanced equation, the mole ratio of HCl to Na2CO3 is 2:1.
3. Therefore, for 2 moles of HCl, moles of Na2CO3 required for reaction = (1/2) x 2 = 1 mol.
4. But the initial amount of Na2CO3 given for reaction with HCl is 4 moles. Now, the reaction needs only 1 mole of Na2CO3. Hence, Na2CO3 is in excess of (4-1) = 3 moles. This amount will remain unreacted in the solution after the reaction.
5. On the other hand, for 4 moles of Na2CO3, mole of HCl required for reaction = (2/1) x 4 = 8 moles. But the initial amount of HCl given for reaction with Na2CO3 is 2 moles. Now, the reaction needs 8 moles of HCl for reaction with Na2CO3. Hence, this 2 moles of HCl is insufficient for reaction with Na2CO3 and will be used up first and, therefore, the HCl is a limiting reactant. It will dictate the production of NaCl.
6. Therefore, HCl is a limiting reactant in the above reaction.