Which of the following has convant bond

Options

A. `Na_(2)S`
B. `AICI_(3)`
C. `NaH`
D. `MgCI_(2)`

Answer

B

Explanation

We know that `AI^(+3)` cation is smaller than `Na^(+)` (because of greater nuclear change) According to Fajans rule small cation polarise anion up to greater extent. Hence `AI^(3+)` polarise `CI^(-)` ion up to greater extent, therefore `AICI_(3)` has covalent bond between `AI` and `CI` atoms.