Question

Which bond angle $\theta$ would result in the maximum dipole moment for the triatomic molecule $X{Y}_2$?

• A. 90⁰
• B. 120⁰
• C. 150⁰
• D. 180⁰

Answer 1

The correct option is A 90⁰

The dipole moment of two dipoles inclined at an angle $\theta$ is given by the equation-
$\mu =(X^2+Y^2+2XYcos\theta {)}^{\frac{1}{2}}cos{90}^{\circ }=0$. As the angle increases from ${90}^{\circ }to{180}^{\circ }$, the value of $cos\theta$ becomes more and more -ve and hence resultant decreases. Thus, dipole moment is maximum when $\theta ={90}^{\circ }$.