GKFix MCQ Question

What is the ionization constant of codeine if pH of 0.005 M solution is 9.95?

• A. 1.6 × 10⁻⁶
• B. 8.91 × 10⁻⁵
• C. 7.94 × 10⁻⁹
• D. 3.2 × 10⁻⁷