Question

The molecule with the highest dipole moment among the following is

• A. carbon dioxide
• B. hydrogen fluoride
• C. hydrogen iodide
• D. hydrogen chloride

Hint:

For HF, HCl, HBr, HI: Electronegativity difference decreases down the group, so dipole moment also decreases: \(HF > HCl > HBr > HI\).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Dipole moment (\(\mu\)) depends on the charge separation (\(q\)) and distance (\(d\)). For diatomic molecules like hydrogen halides, the electronegativity difference between the atoms is the primary factor determining the dipole moment.

Step 2: Detailed Explanation:
1. Carbon dioxide (\(CO_2\)): It is a linear molecule (\(O=C=O\)). The individual \(C=O\) dipoles are equal and opposite, canceling each other out. Total \(\mu = 0\).
2. Hydrogen Halides (HF, HCl, HBr, HI): These are polar diatomic molecules.
3. The dipole moment magnitude follows the order of electronegativity of the halogens: \(F > Cl > Br > I\).
4. Since Fluorine is the most electronegative element, the charge separation in \(H-F\) is the greatest.
5. Therefore, \(HF\) has the highest dipole moment.

Step 3: Final Answer:
Hydrogen fluoride (HF) has the highest dipole moment.