Barrons SAT Subject Test Chemistry, 13th Edition

REMEMBER

pH + pOH = 14

Sample Problem

What is the pOH of a solution whose pH is 3.0?
Substituting 3.0 for pH in the expression

pH + pOH = 14.0

gives

INDICATORS

Some indicators can be used to determine pH because of their color changes
somewhere along this pH scale. Some common indicators and their respective
color changes are given below.

TIP

Notice that each indicator has its own range of color change.

Here is an example of how to read this chart: At pH values below 4.5, litmus is
red; above 8.3, it is blue. Between these values, it is a mixture of the two colors.
In choosing an indicator for a titration, we need to consider if the solution
formed when the end point is reached has a pH of 7. Depending on the type of
acid and base used, the resulting hydrolysis of the salt formed may cause it to be
slightly acidic, slightly basic, or neutral. If the titration is of a strong acid and a
strong base, the end point will be at pH 7 and practically any indicator can be
used. This is because the addition of 1 drop of either reagent will change the pH