Question

The Kₑ for aniline, C₆H₅NH₂, is 4.3 × 10⁻¹⁰. What is the equilibrium expression that accompanies this value?

a) [C₆H₅NH₃⁺][OH⁻] / [C₆H₅NH₂]
b) [C₆H₅NH₂] / [C₆H₅NH₃⁺][OH⁻]
c) [C₆H₅NH₃⁺][OH⁻] × [C₆H₅NH₂]
d) [C₆H₅NH₂] × [C₆H₅NH₃⁺][OH⁻]

Answer 1

The correct equilibrium expression accompanying the base dissociation constant, Ke, for aniline is [C6H5NH3+][OH-] / [C6H5NH2], which is option a).

Step-by-step explanation:

The equilibrium constant, Ke, pertains to the equilibrium state of a chemical reaction.

For aniline, C6H5NH2, which is a weak base, the equilibrium expression associated with its base dissociation constant would be the concentration of the produced ions divided by the concentration of the reactant, as per the reaction below:

Aniline (C6H5NH2) in water dissociates as follows:

C6H5NH2 + H2O ⇌ C6H5NH3+ + OH-

The equilibrium expression is thus: Ke = [C6H5NH3+][OH-] / [C6H5NH2].

Therefore, the correct answer is option a).