Question

Select the most ionic and most covalent compounds respectively from the following. $Cr{O}_5,M{n}_2{O}_7,PbO,Sn{O}_2$

• A. $Cr{O}_5,M{n}_2{O}_7$
• B. $PbO,M{n}_2{O}_7$
• C. $Sn{O}_2,Cr{O}_5$
• D. All of the above.

Answer 1

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

As anion $\left(O^{2-}\right)$ is same, the covalent character in ionic compound will depend upon the size and charge on the cation. According to Fajan's rule, $PbO$ is most ionic because $P{b}^{2+}$ has less polarising power where as $M{n}_2{O}_7$ is most covalent because $M{n}^{7+}$ has higher polarising power.