A lot. The temptation trap usually rears its head on questions from Parts A and C
of the exam. On the day you take the test, there will be many things you know
and some that you don’t know. When you meet up with a type C question that’s
stumping you, you might reach out and grab an answer choice that “sounds
familiar” although it has nothing to do with the question.
Suppose you know that adding an acid to a base increases the hydrogen ion
concentration of the solution. Now, look at this question.
- Which of the following will definitely occur if a quantity of acetic
acid is added to a solution of potassium hydroxide at pH 11?
(A) The number of free protons per liter of solution will
increase.
(B) Titration will tend to neutralize the solution.
(C) The acetic acid will act as a weak base.
(D) Acetate ion will precipitate out of solution.
(E) The pH will remain constant.
The correct answer is A, but if the answer to this question doesn’t leap right out
at you, you might decide to make a dash for something you know. Choice B, by
itself, is a true statement with which you might be familiar; titration between an
acid and a base does tend to neutralize a solution. You might say to yourself,
quickly, quietly, and almost unconsciously: “I’ve heard that statement. It sounds
right.” But B is wrong because it doesn’t answer the question.
You Can Avoid the Temptation Trap
When you find yourself ready to choose an answer because it sounds right, stop
to look at the question again carefully. Then take another look at the answer
choices to see if another of them, although in camouflage, is really a better
answer to the question.
Let’s think about the question we just looked at. We’re adding an acid to a base.
We know that we’ll be lowering the pH of the solution—increasing the hydrogen
ion concentration. Choice A says exactly that—in camouflage. Instead of
referring to hydrogen ions, it refers to free protons. Instead of referring directly
to concentration, or pH, it talks about increasing the number of protons per liter