Answer:
First option is correct, and it's a basic solution
Explanation:
This is actually pretty easy, the solution contains 5.5x10⁻⁵ M of OH⁻, so all we need to do is calculate the hydronium with the following expression:
Kw = [H₃O⁺] [OH⁻]
Solving for hydronium:
[H₃O⁺] = Kw / [OH⁻]
The value of Kw is 1x10⁻¹⁴, so replacing the values we have:
[H₃O⁺] = 1x10⁻¹⁴ / 5.5x10⁻⁵
[H₃O⁺] = 1.818x10⁻¹⁰ M
This is the concentration of hydronium, so the first option is the correct answer.
To know if this solution is acidic, basic, or neutral, let's calculate the pH:
pH = -log[H₃O⁺]
Replacing:
pH = -log(1.818x10⁻¹⁰)
pH = 9.74
This pH is >7 so this solution is basic.
