Question

Which of the following metal oxides are acidic, basic and amphoteric respectively?

• A. $M{n}_2{O}_7,C{r}_2{O}_3,CrO$
• B. $M{n}_2{O}_7,CrO,ZnO$
• C. $V_2{O}_5,C{r}_2{O}_3,CrO$
• D. $ZnO,CrO,C{u}_{2}O$

Answer 1

The correct option is B $M{n}_2{O}_7,CrO,ZnO$

$CrO$ is basic, $C{r}_2{O}_3$ is amphoteric and $Cr{O}_3$ is acidic and gives $H_{2}Cr{O}_4$ and $H_{2}C{r}_2{O}_7$.

$M{n}_2{O}_7$ is acidic & gives $HMn{O}_4$

In vanadium there is gradual change from the

Basic $V_2{O}_3$ to less basic $V_2{O}_4$ and to amphoteric $V_2{O}_5$.

$V_2{O}_4$ dissolves in acids to give $(VO{)}^{2+}$ salts.

$V_2{O}_5$ is, however, amphoteric though mainly acidic and it reacts with alkalies as well as acids to give $(V{O}_4{)}^{3–}$ as well as $V{O}^{2+}$ salts.