Video Transcript
Which of the following oxides is
most likely to be an acidic oxide? (A) CuO, (B) Na2O, (C) MgO, (D)
CaO, (E) CO2.
In this problem, we need to
identify the acidic oxide. In order to answer this question,
let us first discuss oxides, which are compounds that contain at least one oxygen
atom chemically bonded to an atom of another element. Each answer is an oxide since an
atom of oxygen is found within each compound. When we take a look at the other
element within each of the oxides, we should note that Na, sodium; Mg, magnesium;
Ca, calcium; and Cu, copper, are all metals, whereas C, carbon, is a nonmetal.
Let us take a look chemically at
these metal oxides. If one of the metal oxides such as
magnesium oxide, MgO, reacts with water, an alkaline solution such as magnesium
hydroxide, Mg(OH)2, forms. Therefore, metal oxides tend to be
considered basic oxides since they can form an alkaline solution which contains OH-,
or hydroxide ions. Now let us move on to nonmetal
oxides such as carbon dioxide. When CO2 reacts with water,
carbonic acid, H2CO3, forms, which is an acidic solution since it contains the H+,
or hydrogen ion. Since nonmetal oxides form acidic
solutions, they are generally considered to be acidic oxides.
Since option choices (A) CuO,
copper(II) oxide; (B) Na2O, sodium oxide; (C) MgO, magnesium oxide; and (D) CaO,
calcium oxide, all contain a metal, they are all considered basic oxides and are all
the incorrect answer choice. Therefore, option choice (E) carbon
dioxide, CO2, is the correct answer choice for an oxide that is most likely to be an
acidic oxide.