Question

Select the most ionic and most covalent compounds respectively from the following:
$CrO_{5},Mn_{2}O_{7},PbO,Fe_{2}O_{3},SnO_{2}$

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