Final answer:
H2SO4 is the limiting reagent in the reaction with NaOH because it gets consumed first and no additional product can be formed once it is used up, even if more NaOH is added.
Step-by-step explanation:
When adding more NaOH to a fixed amount of H2SO4 does not increase the amount of product formed, it indicates that H2SO4 is the limiting reagent. In a chemical reaction, the limiting reagent is the one that gets consumed first, limiting the amount of product that can be formed. According to the balanced chemical equation H2SO4 (aq) + 2NaOH (aq) → Na2SO4 (aq) + 2H2O(l), one mole of sulfuric acid reacts with two moles of sodium hydroxide to form one mole of sodium sulfate and two moles of water. When the mole ratio is not met due to insufficient H2SO4, adding more NaOH will not yield more product because there is no more H2SO4 left to react with.