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The next 3 questions will walk you through using the Henderson-Hasselbalch equation for the following question. For each step provide a numerical answer. A solution is made by combining 300mL of 0.020M trimethyl amine, that is (CH3)3N and a 500mL of a 0.03M solution of it's conjugate acid, that is (CH3)3NH . The Kb for trimethyl amine is 6.3x10-5. The Henderson-Hasselbalch equation uses pKa not Kb, Calculate the pKa....

User Cheshire
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Answer:

The pKa is 13.0.

Step-by-step explanation:

pKa + pKb = 14

Given, Kb of trimethylamine = 6.3 ×
10^(-5)

pKb = - log (6.3 ×
10^(-5))

= 1.0

⇒ pKa = 14 - pKb = 14 - 1.0

pKa = 13.0

Check: For most weak acids, pKa ranges from 2 to 13.

User Thikonom
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