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Salicylic acid (C₇​H₆​O₃​) reacts with acetic anhydride (C₄​H₅​O₃​) to form acetylsalicylic acid (C₉​H₈​O₄​) and water (H₂​O).

2CC₇​H₆​O₃​(aq)+C₄​H₅​O₃​(aq)→2C₉​H₈​O₄​​(aq)+H₂​O(l)

What is the limiting reactant if 70.0 g of C₇​H₆​O₃​ and 80.0 g of C₄​H5​O₃​ react?

a. Water

b. Salicylic acid

c. Acetic anhydride

d. Acetylsalicylic acid

User Jhnclvr
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Final answer:

To find the limiting reactant, we calculate the number of moles of each reactant. Salicylic acid was found to be the limiting reactant because it would be completely consumed before the acetic anhydride.

Step-by-step explanation:

To determine the limiting reactant in the reaction between salicylic acid (C7H6O3) and acetic anhydride (C4H6O3), we need to calculate the number of moles of each reactant and then use the stoichiometry of the balanced chemical equation.

First, calculate the moles of salicylic acid using its molar mass (138.12 g/mol):

Moles of salicylic acid = 70.0 g / 138.12 g/mol = 0.507 moles

Then, calculate the moles of acetic anhydride using its molar mass (102.09 g/mol):

Moles of acetic anhydride = 80.0 g / 102.09 g/mol = 0.784 moles

According to the balanced equation, it takes 1 mole of acetic anhydride to react with 2 moles of salicylic acid. Therefore, for 0.507 moles of salicylic acid, we would require 0.507/2 = 0.2535 moles of acetic anhydride. Since we have 0.784 moles of acetic anhydride available, acetic anhydride is in excess and salicylic acid is the limiting reactant.

User Doug Fawley
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