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. $CrO_{5}, \, Mn_{2}O_{7}$
• B. $PbO,Mn_{2}O_{7}$
• C. $CrO_{5} , \, Fe_{2} O_{3}$
• D. $CrO_{5}, \, SnO_{2}$

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 $Pb^{2 +}$ and $Mn_{2}O_{7}$ is most covalent as it has $Mn^{+ 7}$ .