Calculate the hydrogen-ion concentration [H+] for the aqueous solution in which [OH–] is 1 x 10–4 mol/L. Is this solution acidic, basic, or neutral? Show your work.

[H⁺] = 1×10⁻¹⁰     →  Basic solution

Explanation:

For this question we need to know, the autoionization of water:

2H₂O (l)  ⇄  H₃O⁺ (aq) + OH⁻(aq)     Kw

Kw = 1ₓ10⁻¹⁴ → [H₃O⁺] . [OH⁻]

1ₓ10⁻¹⁴ /[OH⁻] = [H₃O⁺] → 1ₓ10⁻¹⁴ / 1×10⁻⁴  =  1×10⁻¹⁰

In order to determine if the solution is acidic, basic or neutral we use the pH value.

pH = - log  [H₃O⁺]  → -log 1ₓ10⁻¹⁰  = pH = 10          Basic solution

pH < 7 → Acidic solution

pH = 7 → Neutral solution

pH > 7 → Basic solution

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