Problem: Calculate [OH-], [H+], and the pH of 0.20 M solution of the following amine.a. triethylamine [(C2H5)3N, Kb = 4.0 X 10 -4]

FREE Expert Solution
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FREE Expert Solution

Equilibrium reaction:        (C2H5)3N(aq) + H2O(l) (C2H5)3NH+(aq) + OH-(aq)


Step 1: Construct an ICE chart for the reaction.


Step 2: Write the Kb expression and calculate for Kb.

Kb=productsreactantsKb=[(C2H5)3NH+][OH-][C2H53N]

Solids and liquids are not included in the expression


Step 3: Calculate the equilibrium concentrations.

Kb=xx0.20-xKb=x20.20-x


[C2H53N]initialKb=500; cannot ignore -x

4.0×10-4 (0.20-x)=x20.20-x(0.20-x)8.0×10-5-(4.0×10-4)x=x20=x2+(4.0×10-4)x-8.0×10-5


x=-b±b2-4ac2a

97% (452 ratings)
Problem Details

Calculate [OH-], [H+], and the pH of 0.20 M solution of the following amine.

a. triethylamine [(C2H5)3N, Kb = 4.0 X 10 -4]

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