Question

Select the most ionic and most covalent compounds respectively from the following: ${\text{CrO}}_{\text{5}}{\text{, Mn}}_{\text{2}}{\text{O}}_{\text{7}}{\text{, PbO, Fe}}_{\text{2}}{\text{O}}_{\text{3}}{\text{, SnO}}_{\text{2}}$

• A. $Cr{O}_5,M{n}_2{O}_7$
• B. $PbO,M{n}_2{O}_7$
• C. $Cr{O}_5,F{e}_2{O}_3$
• D. $Cr{O}_5,Sn{O}_2$

Answer 1

Answer: (B)

As anion is same, the covalent character in ionic compound will depend upon the size and charge on the cation. According to fajan's rule,

Covalent nature ∝ charge on cation

$\text{PbO}$ is most ionic as it has $P{b}^{2+}$ and $M{n}_2{O}_7$ is most covalent as it has $M{n}^{+7}$ .