Purchase Solution

Acid-Base Equilibria

Not what you're looking for?

Ask Custom Question

1. Determining Ka. What is the Ka value for a weak acid if a 0.0150-M solution has a pH of 2.67?

2. Calculations With Ka. What is the pH of a 0.250-M benzoic acid solution?

3. Polyprotic Weak Acid. What are pH, [H3O+], [HSO3-], and [SO32-] in a 1.50 M sulfurous acid solution?

4. Calculations With Kb. What is the Kb value for a weak base if a 0.250-M solution has a pOH of 4.7?

5. The pH of a Salt Solution. What is the pH of 0.50-M sodium benzoate? The benzoate ion (C7H5O2-) is the anion of benzoic acid.

Purchase this Solution

Solution Summary

For these questions one must first understand that in chemistry, most things are modelled using an equation. The equation you need to use here is quite basic, and learning how to use it will be essential for your performance on exams.

Solution Preview

For any weak acid HA, we can write its dissociation equation:

HA --> H+ + A-

This a chemical equation, and for it we can then make an equilibrium equation, which is simply reactants over the products.

K = [H+][A-]/[HA]

In this case we will call the equilibrium a Ka.

If we were to run what is sometimes called an ICE table fo r the dissciation reaction...

HA --> H+ + A-
Initial C 0 0
Change -x +x +x
Equilibrium C-x x x

And if we now substitute these values for concentrations into our Ka expression, we will then get the general equation for a weak acid.

Ka = x2/C-x

You can do the same thing for a weak base and arrive at

Kb ...

Purchase this Solution

Free BrainMass Quizzes
Match Elements with their Symbols

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

General Chemistry - Classification of Matter

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


The quiz helps in revising basic concepts about thermochemistry.

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.