Question

Which one of the following orders presents the correct sequence of the increasing basic nature of the given oxides?

• A. $K _{2} O < Na _{2} O < Al _{2} O _{3}< MgO$
• B. $Al _{2} O _{3}< MgO < Na _{2} O < K _{2} O$
• C. $MgO < K _{2} O < Al _{2} O _{3}< Na _{2} O$
• D. $Na _{2} O < K _{2} O < MgO < Al _{2} O _{3}$

Answer 1

Answer: (B)

While moving from left to right in periodic table basic character of oxide of elements will decrease.

$\therefore \ce{ ->[{Al _{2} O _{3}< MgO < Na _{2} O}][{\text{Increasing basic strength

}}]}$

and while descending in the group basic character of corresponding oxides increases.

$\therefore \ce{ ->[{Na _{2} O < K _{2} O}][{\text{Increasing basic strength}

}]}$

$\therefore $ Correct order is

$Al _{2} O _{3} < MgO < Na _{2} O < K _{2} O$