Question

The compound dimethylamine, (CH3)2NH, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibrium that occurs in an aqueous solution of dimethylamine:

Answer 1

Answer:

$K_b=\frac {[(CH_3)_2{NH_2}^+][OH^-]}{[(CH_3)_2NH]}$

Explanation:

Kb is base dissociation constant which is measure of the dissociation of a base into component ions in the water.

The base, (CH₃)₂NH dissociates in water as:

(CH₃)₂NH (aq) + H₂O (l)  ⇄ (CH₃)₂NH₂⁺ (aq) + OH⁻ (aq)

The expression for Kb is:

$K_b=\frac {[(CH_3)_2{NH_2}^+][OH^-]}{[(CH_3)_2NH]}$

Water is present in large amounts and is not written in the expression for Kb.