Question

In a solution at 25°C, the [H+] is 3.5 × 10−6 M. What is the [OH−]?

Answer 1

Kw = [ H+] x [ OH-]

1 x 10⁻¹⁴ = [ 3.5 x 10⁻⁶] x [OH-]

[OH-] = 1 x 10⁻¹⁴ / 3.5 x 10⁻⁶

[OH-] = 2.85 x 10⁻⁹ M