Question

pH of an acid buffer is given by

• A. $\mathrm{pH} = \mathrm{pK}_a + \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$
• B. $\mathrm{pH} = \mathrm{pK}_a - \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$
• C. $\mathrm{pH} = \mathrm{K}_a + \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$
• D. None of the above

Hint:

Buffer pH depends on the ratio of salt to acid concentrations.

Answer 1

The Correct Option is A

Step 1: Conceptual Understanding:
Henderson-Hasselbalch equation for acid buffer.
Step 2: Explanation in Detail:
$\mathrm{pH} = \mathrm{p}K_a + \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$ is the correct equation.
Step 3: Therefore, Stating the Final Answer
The correct expression is $\mathrm{pH} = \mathrm{pK}_a + \log \frac{[\mathrm{Salt}]}{[\mathrm{Acid}]}$.