Ammonia, nh3, is a weak base with a kb = 1.8 x 10-5. in a 0.8m solution of ammonia, which has a higher concentration: ammonia (nh3 or its conjugate acid the ammonium ion (nh4?

Question

Jon Frazier

Chemistry

28 April, 09:06

Ammonia, nh3, is a weak base with a kb = 1.8 x 10-5. in a 0.8m solution of ammonia, which has a higher concentration: ammonia (nh3 or its conjugate acid the ammonium ion (nh4?

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Answers (1)

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Augustus Harding · Answer 1

Answer is: concentration ammonia is higher than concentration of ammonium ion.

Chemical reaction of ammonia in water: NH₃ + H₂O → NH₄⁺ + OH⁻.

Kb (NH₃) = 1,8·10⁻⁵.

c₀ (NH₃) = 0,8 mol/L.

c (NH₄⁺) = c (OH⁻) = x.

c (NH₃) = 0,8 mol/L - x.

Kb = c (NH₄⁺) · c (OH⁻) / c (NH₃).

0,000018 = x² / 0,8 mol/L - x.

solve quadratic equation: x = c (NH₄⁺) = 3,79·10⁻³ mol/L.