Question

Among $Al _{2} O _{3}, SiO _{2}, P _{2} O _{3}$ and $SO _{2}$ the correct order of acid strength is

• A. $Al _{2} O _{3}< SiO _{2}< SO _{2}< P _{2} O _{3}$
• B. $SiO _{2}< SO _{2}< Al _{2} O _{3}< P _{2} O _{3}$
• C. $SO _{2}< P _{2} O _{3}< SiO _{2}< Al _{2} O _{3}$
• D. $Al _{2} O _{3}< SiO _{2}< P _{2} O _{3}< SO _{2}$

Answer 1

Answer: (D)

As the size increases, the basic nature of oxides changes to acidic nature i.e., acidic nature increases.
$SO_{2}>P_{2}O_{3}>SiO_{2}>AlO_{3}$
$\quad$ Acidic$\quad\quad\,\,\,\,$ Weak $\quad$ Amphoteric
$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$$\quad$acidic
$SO _{2}$ and $P _{2} O _{3}$ are acidic as their corresponding acids $H _{2} SO _{3}$ and $H _{3} PO _{3}$ are strong acids.