Calculate the pH at of a solution of trimethylammonium chloride . Note that trimethylamine is a weak base with a of . Round your answer to decimal place.

pH = 11.9

Explanation:

The solution is 0.93M. The pKb is 4.19

The general equation of a weak base, X, is:

Kb = [OH⁻] [XH⁺] / [X]

Where Kb is 10^-pKb = 6.457x10⁻⁵

[OH⁻] and [XH⁺] comes both from the same equilibrium and its concentration, X, is the same = [OH⁻] = [XH⁺] = X

And [X] could be taken as the initial concentration of the weak acid, 0.93M

Kb = [OH⁻] [XH⁺] / [X]

6.457x10⁻⁵ = X² / 0.93M

6x10⁻⁵ = X²

X = 7.749x10⁻³M = [OH⁻]

As pOH = -log[OH⁻]

pOH = 2.11

pH = 14 - pOH

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