Phenypropanoic acid (C₉H₁₀O₂) is a white, crystalline solid with a sweet floral smell widely used in cosmetics and food flavorings. It is a weak monoprotic base with K_a value of 2.2×10^–5. If 750 mg of C₉H₁₀O₂ is dissolved in 500.0 mL of water, calculate the pH of the solution and the percent ionization.

• A. pH = 4.21; % ionization = 3.1%
• B. pH = 3.34; % ionization = 4.6%
• C. pH = 6.58; % ionization = 7.4%
• D. pH = 5.66; % ionization = 5.4%

Answer: (B)