Answer:
[OH⁻] = 1.1 × 10⁻³ M
Step-by-step explanation:
An aqueous solution at 25°C has a H₃O⁺ concentration of 8.8 × 10⁻¹² M. Calculate the concentration of OH⁻. Be sure your answer has 2 significant digits.
Step 1: Given data
Concentration of H₃O⁺ ([H₃O⁺]): 8.8 × 10⁻¹² M
Concentration of OH⁻ ([OH⁻]): ?
Step 2: Calculate the concentration of OH⁻
Let's consider the self-ionization of water.
2 H₂O(aq) ⇄ H₃O⁺(aq) + OH⁻(aq)
The equilibrium constant for this reaction is:
Kw = [H₃O⁺] × [OH⁻] = 1.0 × 10⁻¹⁴
[OH⁻] = 1.0 × 10⁻¹⁴ / [H₃O⁺]
[OH⁻] = 1.0 × 10⁻¹⁴ / 8.8 × 10⁻¹²
[OH⁻] = 1.1 × 10⁻³ M