Purchase Solution


Not what you're looking for?

Ask Custom Question

5) Using the following pKb (pKb = 4.11) of an unknown base, calculate the Ka of the corresponding conjugate acid and use the Ka value to identify the unknown base. Be careful to show all the steps used to convert pKb to Ka.
(See attachment for data)

6) Potassium hydrogen phthalate (KHP, K+OOC-C6H4-COOH) is a carboxylic acid which can be accurately weighed and yeilds solutions of stable pH. For this reason, KHP is used to standardize alkaline solution and to calibrate instruments capable of measuring pH.

25.00 mL of 0.7692 M KHP solution was titrated using 0.1000 M NaOH.

a) Calculate the pH of the KHP solution before the titration begins (Ka = 3.91 x 10^-6)
b) Calculate the pH of the NaOH solution before the titration begins.
c) Calculate the pH at the equivalence point.
d) Calculate the pH after the addition of 29.23 mL of NaOH solution.

Purchase this Solution

Solution Summary

Titrations are examined. The expert determines how to calibrate instruments which are capable of measuring pH is determined.

Solution Preview

5. pKb = 4.11

pKa + pKb = 14

pKa = 14 - pKb = 14 - 4.11 = 9.89

-log(Ka) = 9.89

Ka = 10^(-9.89) = 1.29 x 10^(-10) = 1.3 x 10^(-10)

Hence it must be the conjugate base of phenol which is phenolate.

6. Let KHP be abbreviated as HA as it is a monoprotic acid.

a) HA -----> H+ + A-

Initial 0.7692M 0 0

Change -y +y +y

Equilibrium 0.7692 - y y y

Ka = [H+][A-] / [HA] = y^2 / (0.7692 - y) = 3.91 x 10^(-6)

y^2 = 3.00 x 10^(-6) - 3.91x10^(-6)y

Solving the quadratic equation ...

Purchase this Solution

Free BrainMass Quizzes
Organic Chemistry Naming: Alkanes

This is a quiz which is designed to assist students with learning the nomenclature used to identify organic compounds. This quiz focuses on the organic compounds called Alkanes.


The quiz helps in revising basic concepts about thermochemistry.

General Chemistry - Classification of Matter

This test will assess your knowledge on the classification of matter which includes elements, compounds and mixtures.

Match Elements with their Symbols

Elements are provided: choose the matching one- or two-letter symbol for each element.