Answer to Question #170664 in Chemistry for Hyeri

Question

What concentration of hydroxide ions exist in a 0.008 F solution of NH3 at 25°C .

Answer 1

In solution, NH₃ dissociates as follows:

NH₃ + H₂O = NH₄⁺ + OH^-

Dissociation constant:

K_b = [NH₄⁺][OH^-] / [NH₃]

From here:

[OH^-] = [NH₄⁺] = (K_b × [NH₃])^1/2 = (1.8 × 10^-5 × 0.008 F) = 3.8 × 10^-4 F

Answer: 3.8 × 10^-4 F