Question

Among the oxides SiO\(_2\), SO\(_2\), Al\(_2\)O\(_3\), and P\(_2\)O\(_5\), the correct order of acidic strength is:

• A. \(\text{SiO}_2<\text{SO}_2<\text{Al}_2\text{O}_3<\text{P}_2\text{O}_5\)
• B. \(\text{SO}_2<\text{P}_2\text{O}_5<\text{Al}_2\text{O}_3<\text{SiO}_2\)
• C. \(\text{Al}_2\text{O}_3<\text{SiO}_2<\text{P}_2\text{O}_5<\text{SO}_2\)
• D. \(\text{Al}_2\text{O}_3<\text{P}_2\text{O}_5<\text{SiO}_2<\text{SO}_2\)

Hint:

The acidity of oxides increases with the electronegativity of the central atom in non-metal oxides.

Answer 1

The Correct Option is C

The acidic strength of these oxides increases from Al\(_2\)O\(_3\) (amphoteric) to SiO\(_2\) (weakly acidic) to P\(_2\)O\(_5\) (strongly acidic) and then to SO\(_2\) (more acidic due to its ability to form sulfurous acid upon hydration).