Ammonia is a weak base. if the initial concentration of ammonia is 0.150 m and the equilibrium concentration of hydroxide is 0.0016m, calculate kb for ammonia.

Question

Larry Hansen

Chemistry

31 October, 11:52

Ammonia is a weak base. if the initial concentration of ammonia is 0.150 m and the equilibrium concentration of hydroxide is 0.0016m, calculate kb for ammonia.

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Scott Nichols · Answer 1

Answer is: Kb for ammonia is 1.73·10⁻⁵.

Chemical reaction of ammonia in water: NH ₃ + H₂O → NH₄⁺ + OH⁻.

Kb (NH ₃) = ?.

c ₀ (NH₃) = 0.150 M.

c (NH ₄⁺) = c (OH⁻) = 0.0016 M.

c (NH ₃) = 0.150 M - 0.0016.

c (NH₃) = 0.1484 M.

Kb (NH₃) = c (NH₄⁺) · c (OH⁻) / c (NH₃).

Kb (NH₃) = (0.0016 M) ² / 0.1484 M.

Kb (NH₃) = 1.73·10⁻⁵.