Question

The fizz produced when an alka-seltzer® tablet is dissolved in water is due to the reaction between sodium bicarbonate (nahco3) and citric acid (h3c6h5o7): 3nahco3(aq)+h3c6h5o7(aq)→3co2(g)+3h2o(l)+na3c6h5o7(aq) in a certain experiment 1.50 g of sodium bicarbonate and 1.50 g of citric acid are allowed to react.

Answer 1

Answer is: sodium bicarbonate is the limiting reagent.

Balanced chemical reaction:

3NaHCO₃(aq) + H₃C₆H₅O₇(aq) → 3CO₂(g) + 3H₂O(l) + Na₃C₆H₅O₇(aq).

n(NaHCO₃) = m(NaHCO₃) ÷ M(NaHCO₃).

n(NaHCO₃) = 1.50 g ÷ 84 g/mol.

n(NaHCO₃) = 0.0178 mol.

n(H₃C₆H₅O₇) = 1.50 g ÷ 192.12 g/mol.

n(H₃C₆H₅O₇) = 0.0078 mol.

From chemical reaction: n(NaHCO₃) : n(H₃C₆H₅O₇) = 3 : 1.

n(NaHCO₃) : 0.0078 mol = 3: 1.

n(NaHCO₃) = 0.0234 mol; amount of substance need to react with citric acid, so we conclude there is no enough sodium bicarbonate.