Question

or neutral. Calculate the concentration of OH- in a solution that contains 3.9 x 10-4 M H3O+ at 25°C. Identify the solution as acidic, basic or neutral. 3.9 × 10-4 M, neutral 2.7 × 10-2 M, basic 2.6 × 10-11 M, basic 2.7 × 10-2 M, acidic 2.6 × 10-11 M, acidic

Answer 1

Answer:

[OH⁻] = 2,6x10⁻¹¹

Acidic

Explanation:

The kw in water is:

2 H₂O(l) ⇄ OH⁻(aq) + H₃O⁺(aq)

kw = [OH⁻] [H₃O⁺] = 1,00x10⁻¹⁴

If concentracion of H₃O⁺ is 3,9x10⁻⁴M:

[OH⁻] [3,9x10⁻⁴M] = 1,00x10⁻¹⁴

[OH⁻] = 2,6x10⁻¹¹

pH is defined as - log[H₃O⁺]. If pH>7,0 the solution is basic, if pH<7,0 solution is acidic, if pH=7,0 solution is neutral.

In this problem,

pH = - log [3,9x10⁻⁴M] = 3,4

As pH is < 7.0, the solution is acidic

I hope it helps!