Which of the following oxide is amphoteric ?

Question

Which of the following oxide is amphoteric ? (A) SnO2 (B) CaO (C) SiO2 (D) CO2

Tardigrade Admin · Accepted Answer

In general, the electropositive character of the oxide's central atom will determine whether the oxide will be acidic or basic. The more electropositive the central atom the more basic the oxide. The more electronegative the central atom, the more acidic the oxide. Electropositive character increases from right to left across the periodic table and increases down the column.

S n O_{2}

is an amphoteric oxide because it reacts with acids as well as bases to form corresponding salts.

< b r / > S n O_{2} + 2 H^{+} ⟶ S n^{4 +} + 2 H_{2} O < b r / >

< b r / > S n O_{2} + 6 O H^{-} ⟶ [S n (O H)_{6}]^{2 -} or S n O_{3}^{2 -} (stannate) < b r / >

C a O

is basic.

S i O_{2}

and

C O_{2}

are acidic in nature.
Silicon dioxide has no basic properties - it doesn't contain oxide ions and it doesn't react with acids. Instead, it is very weakly acidic, reacting with strong bases.

C a O

is basic in nature and

C O_{2}

is acidic in nature.

Q. Which of the following oxide is amphoteric ?

SnO2​

CaO

SiO2​

CO2​

$S n O_{2}$

$C a O$

$S i O_{2}$

$C O_{2}$