Among `Al_(2)O,SiO_(2),P_(2)O_(3)` and `So_(2)` the correct order of acid strength is

Options

A. `SO_2 lt P_2O_3 lt SiO_2 lt Al_2O_3`
B. `SiO_2 lt SO_2 lt Al_2O_3 lt P_2O_3`
C. `Al_2O_3 lt SiO_2 lt SO_2 lt P_2O_3`
D. `Al_2O_3 lt SiO_2 lt P_2O_3 lt SO_2`

Answer

D

Explanation

With decrease in size from Al to S the basic nature of oxides decreases and acidic nature increases.
`Al_2O_3 lt SiO_2 lt P_2O_3 lt SO_2`
`Al_2O_3` is amphoteric , `SiO_2` is slightly acidic, `P_2O_3` and `SO_2` are anhydrides of the acids `H_3PO_3` and `H_2SO_3`.`H_2SO_3` is a stronger acid than `H_3PO_3`