Question

Which compound among the following has the least ionic character?

• A. $\mathrm{AgCl}$
• B. $\mathrm{KCl}$
• C. ${\mathrm{CaCl}}_2$
• D. ${\mathrm{BaCl}}_2$

Answer 1

The correct option is A

$\mathrm{AgCl}$

Ionic compounds

Ionic compounds are made up of ions with the opposite charge. They are crystalline solids that are produced when metal reacts with non-metals. Ionic bonds are what hold them together. The size of cations and anions are used in the structural determination of ionic compounds.

The least ionic compound is $\mathrm{AgCl}$.

Fajan's rule is utilized to answer this question, in which some chemical compounds are classified as ionic or covalent.
Fajan's rule is based on a few precepts. Let's have a look at these premises:

• Size of the ion: If the cation is smaller and the anion is larger, the ionic bond's covalent character improves.
• The charge of the cation: As the charge of the cation grows, so does the covalent character of the ionic bond.

According to the postulates, the size of the cation diminishes as we move left to right in a period, and the ionic character lowers as well. Among $\mathrm{Ag},\mathrm{K},\mathrm{Ca},\mathrm{Ba}$, $\mathrm{Ag}$ is a $\mathrm{d}$ block element and the remaining are $\mathrm{S}-$ block elements.

Therefore, $\mathrm{AgCl}$ is the least ionic compound among the given ionic compounds.

Hence the correct option is (A).