Question

Which of the following oxides is most acidic in nature ?

• A. CaO
• B. MgO
• C. BaO
• D. BeO

Answer 1

The Correct Option is D

To determine which oxide is most acidic in nature, let's analyze the given options: CaO, MgO, BaO, and BeO.

1. The nature of an oxide is often determined by the position of the element in the periodic table. Elements towards the left and middle (e.g., alkali and alkaline earth metals) tend to form basic oxides, whereas non-metals usually form acidic oxides.
2. For alkaline earth metals such as calcium (Ca), magnesium (Mg), barium (Ba), and beryllium (Be), the oxide’s acidity or basicity can be discussed in terms of both atomic number and periodic trends.
3. The oxides of metals generally tend to be basic. However, the acidity of the oxides increases from left to right across a period and from bottom to top in a group.
4. In the group of alkaline earth metals (Group 2), BeO tends to show amphoteric properties, which means it can act both as a base and, to a lesser extent, as an acid. However, compared to others in this group, it is the closest to borderline acidic behavior because of its position.
5. CaO, MgO, and BaO are basic oxides. As we move down the group from Be to Ba, the basicity increases, making BeO the least basic and relatively more acidic among these options.

Considering these points, BeO is the most acidic among the given options. It exhibits slight acidic behavior as compared to the other oxides, which are largely basic.