Among the following the maximum covalent character is shown by the compound

The correct option is AlCl₃.

To determine which compound shows the maximum covalent character, we can apply Fajans' Rules. According to Fajans' rules, the covalent character in an ionic bond increases with the increase in the polarization of the anion by the cation. Polarization is favored by:
1. Small size of the cation.
2. Large size of the anion.
3. High charge on either the cation or the anion.
4. Pseudo-noble gas configuration of the cation (18 electrons in the outermost shell) compared to a noble gas configuration (8 electrons in the outermost shell).

Let us analyze the given compounds: MgCl₂, FeCl₂, SnCl₂, and AlCl₃. Since the anion (Cl^-) is the same in all these compounds, the covalent character depends entirely on the nature of the cation.

The cations in the respective compounds and their charges (oxidation states) are:
• In MgCl₂, the cation is Mg²⁺.
• In FeCl₂, the cation is Fe²⁺.
• In SnCl₂, the cation is Sn²⁺.
• In AlCl₃, the cation is Al³⁺.

Comparing the charges on the cations:
The charge on the aluminum ion (Al³⁺) is +3, whereas the charge on Mg²⁺, Fe²⁺, and Sn²⁺ is only +2.

According to Fajans' rules, a higher positive charge on the cation results in a stronger electrostatic attraction for the electron cloud of the anion (Cl^-). This leads to a greater polarization (distortion) of the anion's electron cloud, which significantly increases the share of electrons between the cation and the anion, thereby maximizing the covalent character.

Furthermore, Al³⁺ has a very small ionic radius. The combination of a high charge (+3) and small size gives Al³⁺ a very high charge-to-size ratio (polarizing power) compared to Mg²⁺, Fe²⁺, and Sn²⁺.

Therefore, AlCl₃ exhibits the maximum polarization of the chloride ion and consequently shows the maximum covalent character among the given options.