Question

Which of the following has correct increasing basic strength? 
a. MgO < BeO < CaO < BaO
b. BeO < MgO < CaO < BaO
c. BaO < CaO < MgO < BeO
d. CaO < BaO < BeO < MgO

Answer 1

Hint:All the oxides are given in the option are made up of group 2 elements i.e., alkaline earth metals. The basic character of the oxides increases on moving down the group.

Complete step-by-step answer:
Oxides are chemical compounds containing at least one oxygen atom and any other element in their chemical formula.
Basic oxides are formed by the reaction of an oxygen atom with an electropositive metal. Basic oxides usually show basic characteristics.
The basic oxides are also termed basic anhydride which means “base without water”.
When they are dissolved in water, they produce a base and when they react with an acid, they form salt and water.
The electropositive nature of the oxide determines the basic strength of the oxides. The more the electropositive value of the metal, the more basic its oxide will be. The electropositive characteristic of a metal increases on moving right to left in the periodic table whereas increases on moving down in the column.
The elements given are group 2 elements and the order of the elements is Be, Mg, Ca, Sr, Ba. Beryllium is present at the top of the column and Barium is present at the bottom of the column.
So, barium oxide will be the most basic in nature.
Hence, the correct order is BeO < MgO < CaO < BaO.

This implies that the correct option is (b).

Note: Among the given oxides, Beryllium oxide is an amphoteric oxide which means that it shows properties of both basic oxide and acidic oxide.