The compound trimethylamine, (CH3)3N, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibrium that occurs in an aqueous solution of trimethylamine:

Respuesta :

Answer:

The [tex]K_b[/tex] expression for the weak base equilibrium is:

[tex]K_b=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}[/tex]

Explanation:

[tex](CH_3)_3N(aq)+H_2O(l)\rightlefharpoons (CH_3)_3NH^++OH^-(aq)[/tex]

The expression of the equilibrium constant of base [tex]K_c[/tex] can be given as:

[tex]K_c=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N][H_2O]}[/tex]

][tex]K_b=K_c\times [H_2O]=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}[/tex]

As we know, water is pure solvent, we can put [tex][H_2O]=1[/tex]

[tex]K_b=K_c\times 1=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}[/tex]

So, the the [tex]K_b[/tex] expression for the weak base equilibrium  is:

[tex]K_b=\frac{[(CH_3)_3NH^+][OH^-]}{[(CH_3)_3N]}[/tex]