Question

The dipole moment of `LiH` is `1.964 xx10^(-29)C-m` and the interatomic diatance between `Li` and `H` in this molceule is `1.596Å` .What is the per cent ionic character in `LiH`.
A. `75.0`
B. `76.8`
C. `79.8`
D. 100

Answer 1

Correct Answer - B
The dipole moment of 100% ionic molecule = (1 electronic charge) `xx` (interatomic distance)
` = 1.602 xx 10^(-19) xx 1.596 xx 10^(-10) = 2.557 xx 10^(-29) ` cm
Fractional ionic character = ` "Exp. Value of dipole moment "/"Theoretical value of dipole moment " = (1.964 xx 10^(-29))/(2.557 xx 10^(-29)) = 0.768`
The bond in LiH is ` 76.8%` ionic.