Question

The most basic oxide is:
A. ${\rm{BeO}}$
B. ${\rm{CaO}}$
C. ${\rm{BaO}}$
D. ${\rm{MgO}}$

Answer 1

We know that the oxides are those chemical compounds in which one or more than one oxygen is bonded with other elements. In oxide compounds, one oxygen is present in the formula. In the periodic table, from top to bottom, the metallic character increases.

Complete step by step solution
As we all know, the oxides are generally forms of basic compounds. In the periodic table, group $1$ and group $2$ gives the basic oxides. They are generally named metal oxides because all the elements present in these first groups are metals. When we are moving from up to down, the metallic character increases, so that means the basic character of those elements also increases.

Thus, in group $2$, the elements are termed as alkaline earth metals. They have six elements : beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). So, the basic character increases from moving up to down, which means the most basic oxide of the alkaline group is BaO because it has maximum metallic character.

The compound ${\rm{BaO}}$ is one of the most basic in nature as the basic character increases from moving up to down in the group.
**Hence, the correct answer to this given question is C that is ${\rm{BaO}}$.

Note: **
One should know the correct relation between metallic character and basicity down the group in the periodic table. The famous basic oxides of the alkaline group are magnesium oxide, calcium oxide, barium oxide, and beryllium oxide. The magnesium oxide that is ${\rm{MgO}}$ is used as a good thermal conductor. The ${\rm{CaO}}$ is famous as lime or quicklime. The lime can be produced by the decomposition of calcium carbonate. It has a milky solution.