Question

Which one of the following is most acidic?

• A. $A{l}_2{O}_3$
• B. $N{a}_{2}O$
• C. $MgO$
• D. $CaO$

Answer 1

The correct option is A $A{l}_2{O}_3$

$N{a}_{2}O,MgO,CaO$ are metallic oxide of $sblock$. These metallic oxides are powerful bases, while $A{l}_2{O}_3$ is metallic oxide of $pblock$ which has comparatively more acidic character. Hence, it is the most acidic oxide among all.