# Problem: What is the pH of 0.688 M trimethylammonium iodide, (CH3)3NHI? Enter your answer with two decimal places. The Kb of trimethylamine, (CH3)3N, is 6.3 x 10-5.a. 3.68b. 0.16c. 9.79d. 4.98e. 7.00

###### FREE Expert Solution

We are being asked to calculate the pH of a 0.688 M trimethylammonium iodide, (CH3)3NHI.

(CH3)3NHI is a salt and it will break up in the solution:

(CH3)3NHI(aq) → (CH3)3NH+(aq) + I-(aq)

(CH3)3NH+ is the conjugate acid of a weak base ((CH3)3N):

(CH3)3N    +   H2O(l)    →    (CH3)3NH+(aq)    +    OH-(aq)
(weak base)                                 (conjugate acid)

Since we’re dealing with a weak acid, we will have to create an ICE chart to determine the equilibrium concentration of each species:

(CH3)3NH+ weak acid proton donor
H2O → will act as the weak base proton acceptor

Equilibrium reaction:        (CH3)3NH+(aq) + H2O(l)  (CH3)3N(aq) + H3O+(aq)

###### Problem Details

What is the pH of 0.688 M trimethylammonium iodide, (CH3)3NHI? Enter your answer with two decimal places.

The Kb of trimethylamine, (CH3)3N, is 6.3 x 10-5.

a. 3.68
b. 0.16
c. 9.79
d. 4.98
e. 7.00