Question

Which substance has the greatest ionic character ?

• A. $ Cl_2O $
• B. $ NCl_3 $
• C. $ PbCl_2 $
• D. $ BaCl_2 $

Answer 1

Answer: (D)

(i) Covalent character $\propto \frac{1}{\text { size of cation }} \propto$ size of anion

(according to Fajan's rule)

(ii) Lower the covalent character, higher will be ionic character.

$Cl _{2} O$, contains $O ^{2-}, NCl _{3}$ contains $N ^{3-}, PbCl _{2}$

contains $Pb ^{2+}$ and $BaCl _{2}$ contains $Ba ^{2+}$.

Hence, the order of covalent character is

$NCl _{3}> Cl _{2} O > PbCl _{2}> BaCl _{2}$

$\therefore BaCl _{2}$ has the greatest ionic character.