Question

Calculate the concentration of H3O+ of a solution if the concentration of OH- at 25°C is 3.8 × 10-5 M and determine if the solution is acidic or basic.

Answer 1

Answer:

[H₃O⁺] = 2.63×10⁻¹⁰ M

As pH = 9.57, the solution is basic

Explanation:

We must know this knowledge:

[OH⁻] . [H₃O⁺] = 1×10⁻¹⁴

3.8×10⁻⁵ . [H₃O⁺] = 1×10⁻¹⁴

[H₃O⁺] = 1×10⁻¹⁴ / 3.8×10⁻⁵ → 2.63×10⁻¹⁰ M

Let's determine the pH to state if the solution is acidic or basic

pH < 7 → acidic ; pH > 7 → basi

pH = - log [H₃O⁺]

pH = - log 2.63×10⁻¹⁰ → 9.57