Which bond angle, `theta` would result in the maximum dipole moment for the triatomic molecule `XY_2` ?

Options

A. `theta = 90^@`
B. `theta = 120^@`
C. `theta = 150^@`
D. `theta = 180^@`

Answer

A

Explanation

The dipole moment of two dipoles inclined at an angle `theta` is given by the equation `mu = sqrt(X^2 +Y^2 + 2XY cos theta) cos 90^@ = 0`. Since the angle increases from 180 90  , the value of `cos theta`becomes more and more – ve and hence resultant decreases. Thus, dipole moment is maximum when `theta = 90^@`.