Given a weak acid solution with a pKa of 4.75 and a ratio of conjugate base to conjugate acid of 0.1, calculate the pH using the Henderson Hasselbalch equation.

• A. pH = 4.75 + log(0.1) = 4.75 - 1 = 3.75
• B. pH = 4.75 + log(0.1) = 4.75 - 0.1 = 4.65
• C. pH = 4.75 + log(0.1) = 4.75 + 0.1 = 4.85
• D. pH = 4.75 + log(0.1) = 4.75 + 1 = 5.75

Answer: (A)