Answer to Question #85166 in General Chemistry for C

Question

Anhydride means “without water.” Suppose 1 M H2SO4 were substituted for the conc H2SO4. Would the yield of acetylsalicylic acid be increased, decreased, or unaffected by the substitution? Explain.

Answer 1

Supposing that you are making acetyl salicylic acid (Aspirin) from salicylic acid with acetic anhydride, the reason why you are adding the conc H2SO4 (or H3PO4) is because you are removing an OH and forming an ester (ROOR). In most cases the H2SO4 is responsible for removing the OH and since you are reacting it with salicylic acid you form an ester. This process is called esterification. The yield will decreased.