Question

The acid dissociation constant for \( HC_6H_7O_6 \) is \( 8.0 \times 10^{-5} \). If a solution contains equal concentrations of \( HC_6H_7O_6 \) and \( C_6H_7O_6^- \), what will be the pH of the solution?

• A. 3.0
• B. 4.1
• C. 5.3
• D. 9.0

Hint:

For buffer solutions with equal concentrations of an acid and its conjugate base, the pH is the \(pK_a\) of the acid.

Answer 1

The Correct Option is B

Since the solution contains equal concentrations of the acid and its conjugate base, the pH is determined using the \(pK_a\) of the acid. The pH is given by the formula \(pH = \dfrac{pK_a}{2} = 4.1\).