Three acids found in foods are lactic acid (in milk products), oxalic acid (in rhubarb), and malic acid (in apples). The pK_a values are LA = 3.88, OA = 1.23, and MA = 3.40. Which list has these acids in order of decreasing acid strength?

Question

Quizplus · Accepted Answer

The order should be based on the pKas of the acids, with the strongest acid having the lowest pKa. Therefore, the order should be: OA (pKa 1.23) > MA (pKa 3.40) > LA (pKa 3.88). Choice C lists the acids in this order, so it is the correct choice.

Three Acids Found in Foods Are Lactic Acid (In Milk