Question

PH-UL unei soluții este5.ce pOH va avea solutia?

Answer 1

Metoda I:

pH+pOH = 14 => pOH =14-5 = 9

[OH⁻] = 10⁻pOH = 10⁻⁹ mol/L

Metoda II:

[H₃O⁺] = 10⁻pH = 10⁻⁵

Kw = [OH⁻]*[H₃O⁺] = 10⁻¹⁴ (mol/L)²  => [OH⁻] = 10⁻¹⁴/10⁻⁵ = 10⁻⁹ mol/L

pOH = -lg[OH⁻] = -lg 10⁻⁹ = 9