Question

In a Bowler's solution containing the same concentrations of B^- and HB, the ratio of K_B to B^- is 10^-10. The pH of the Bowler's solution will be:

• A. 4
• B. 6
• C. 7
• D. 10

Hint:

For a buffer solution containing a weak acid (HA) and its conjugate base ($\text{A}^-$), if $[\text{HA}] = [\text{A}^-]$, then $\text{pH} = \text{p}\text{K}_{\text{a}}$. Similarly, for a buffer containing a weak base (B) and its conjugate acid ($\text{BH}^+$), if $[\text{B}] = [\text{BH}^+]$, then $\text{pOH} = \text{p}\text{K}_{\text{b}}$. Always remember the relationship $\text{pH} + \text{pOH} = 14$ and $\text{p}\text{K}_{\text{a}} + \text{p}\text{K}_{\text{b}} = 14$.