Answer:
[OH⁻] = 4.0 × 10⁻⁹ M
Acidic
Explanation:
Step 1: Given data
- Concentration of H₃O⁺: 2.5 × 10⁻⁶ M
Step 2: Calculate the concentration of OH⁻
We will use the following expression.
[H₃O⁺].[OH⁻] = Kw = 1.0 × 10⁻¹⁴
[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 1.0 × 10⁻¹⁴/2.5 × 10⁻⁶ = 4.0 × 10⁻⁹ M
Step 3: Calculate the pH
We will use the following expression.
pH = -log [H₃O⁺] = -log 2.5 × 10⁻⁶ = 5.6
Since the pH < 7, the solution is acidic.
