Question

You have a solution that is 0.02M formate (HCOO-) and 0.03M formic acid (HCOOH), which has a Ka of 1.8x10-4. What is the pH of the solution

Answer 1

Answer:

3.6

Explanation:

Step 1: Given data

• Concentration of formic acid: 0.03 M

• Concentration of formate ion: 0.02 M

• Acid dissociation constant (Ka): 1.8 × 10⁻⁴

Step 2: Calculate the pH

We have a buffer system formed by a weak acid (HCOOH) and its conjugate base (HCOO⁻). We can calculate the pH using the Henderson-Hasselbach equation.

$pH = pKa +log\frac{[base]}{[acid]} = -log 1.8 \times 10^{-4} + log \frac{0.02}{0.03} = 3.6$