Question

The amphoteric oxide among the following is:

• A. $C{r}_2{O}_3$
• B. $M{n}_2{O}_7$
• C. $V_2{O}_3$
• D. $CrO$

Answer 1

Answer: (A)

$C{r}_2{O}_3$

If the central metal atom is present in its lowest oxidation state, the oxide is basic. If present in the highest oxidation state, the oxides are acidic and if present in intermediate oxidation state, the oxide is amphoteric.

$\text{Oxide}$	$\text{Oxidation state of central atom}$	$\text{Nature}$
$C{r}_2{O}_3$	$+3$	Amphoteric
$M{n}_2{O}_7$	$+7$	Acidic
$V_2{O}_3$	$+3$	Basic
$CrO$	$+2$	Basic

Hence, option $A$ is correct.