Henderson-Hasselbalch Equation Practice Test

A buffer is made from benzoic acid and benzoate, $\text{C}_6\text{H}_5\text{COOH}/\text{C}_6\text{H}_5\text{COO}^-$. If $\text{C}_6\text{H}_5\text{COO}^-=0.040\ \text{M}$ and $\text{C}_6\text{H}_5\text{COOH}=0.010\ \text{M}$ and $pK_a=4.20$, what is the pH?

Two buffers are prepared using the same conjugate acid-base pair $\text{HA}/\text{A}^-$. For Buffer 1, $\text{A}^-/\text{HA}=10$. For Buffer 2, $\text{A}^-/\text{HA}=0.10$. Which statement correctly compares the pH values?