Answer:
305 mg
Explanation:
The equation of the reaction is;
C9H8O4 + NaOH = C9H7O4Na + H2O
Amount of NaOH reacted = 15.5/1000 L * 0.109 M = 1.69 * 10^-3 moles
Since the reaction has a 1:1 mole ration, 1.69 * 10^-3 moles of acetylsalicylic acid reacted.
Assuming all the acetylsalicylic acid reacted, then mass of acetylsalicylic acid present = 1.69 * 10^-3 moles * 180.158 g/mol = 0.305 g or 305 mg