Question

The most ionic compound among the following is:

• A. silica
• B. aluminium fluoride
• C. carborundum
• D. aluminium chloride

Answer 1

The correct option is B aluminium fluoride

Silica, $Si{O}_2$ - $Si{O}_2$ is a giant covalent molecule.

In $Al{F}_3$, $Al$ is electropositive and $F$ is highly electronegative., hence, $Al{F}_3$ is ionic.
Carborundum, $SiC$ is a covalent molecule.
Aluminium chloride, $AlC{l}_3$ is partially ionic and partially covalent.
As electronegativity of fluorine is more than chlorine, $Al{F}_3$ is more ionic than $AlC{l}_3$.
So, $Al{F}_3$ is the most ionic compound in given compounds.