Question

[please answer fast!] If the hydroxide ion concentration is 2x10^-3 M, what is the pH of the solution? Show your working.

Answer 1

pH = 11.30

Step-by-step explanation:

pH is defined as -log [H⁺]

To find [H⁺] from [OH⁻] -Concentration of hydroxide ion-, we must use the equilibrium of water:

H₂O(l) ⇄ H⁺(aq) + OH⁻(aq)

Keq = 1x10⁻¹⁴ = [H⁺] [OH⁻]

[H⁺] = 1x10⁻¹⁴ / [OH⁻]

[H⁺] = 1x10⁻¹⁴ / 2x10⁻³M

[H⁺] = 5x10⁻¹²M

pH = -log (5x10⁻¹²M)

pH = 11.30