Question

Which of the following molecules is a polar molecule?

• A. Oxygen (O\(_2\))
• B. Hydrogen (H\(_2\))
• C. Carbon dioxide (CO\(_2\))
• D. Hydrogen Chloride (HCl)

Hint:

To identify polar molecules, check for a significant electronegativity difference between atoms and an asymmetric molecular shape that does not allow for dipole cancellation.

Answer 1

The Correct Option is D

Step 1: Understanding polarity of molecules.
A polar molecule is one in which the electrons are not equally shared between atoms, leading to a dipole moment. This occurs when there is a significant difference in electronegativity between the atoms.
Step 2: Analyzing the options.
- (A) Oxygen (O\(_2\)): Oxygen is a diatomic molecule with equal electronegativity, so it is non-polar.
- (B) Hydrogen (H\(_2\)): Similar to oxygen, hydrogen is a diatomic molecule with equal electronegativity, so it is non-polar.
- (C) Carbon dioxide (CO\(_2\)): Despite having polar bonds, the linear shape of CO\(_2\) makes it a non-polar molecule because the dipoles cancel each other out.
- (D) Hydrogen chloride (HCl): HCl has a polar bond because chlorine is much more electronegative than hydrogen, making it a polar molecule.
Step 3: Conclusion.
Thus, HCl is a polar molecule, corresponding to option (D).