Question

Amongst $LiCl,RbCl,BeC{l}_2$ and $MgC{l}_2,$ the compounds with greatest and the least ionic character, respectively are

• A. $LiCl$ and $RbCl$
• B. $RbCl$ and $BeC{l}_2$
• C. $RbCl$ and $MgC{l}_2$
• D. $MgC{l}_2$ and $BeC{l}_2$

Answer 1

Answer: (B)

Smaller cation with large magnitude of charge $(B{e}^{2+})$ leads to more covalent character i.e., less ionic character and large cation with small magnitude of charge $(R{b}^{+})$ leads to less covalent character i.e., more ionic character according to Fajan rule. Thus $RbCl$ is most ionic and $BeC{l}_2$ is least ionic.