Answer:
2.90 × 10⁻³
Explanation:
Step 1: Given data
pH: 1.80
Concentration of the weak acid (Ca): 0.086 M
Step 2: Calculate the concentration of H⁺
We will use the following expression.
pH = -log [H⁺]
[H⁺] = antilog -pH = antilog -1.80
[H⁺] = 0.0158 M
Step 3: Calculate the acid dissociation constant (Ka)
We will use the following expression.
Ka = [H⁺]² / Ca
Ka = 0.0158² / 0.086
Ka = 2.90 × 10⁻³
