Question

The centre of negative charge distribution in a molecule may or may not coincide with the centre of the positive charge distribution. If it does not coincide, each molecule has a permanent dipole moment. Such materials are called

• A. polar materials
• B. non-polar materials
• C. ionic materials
• D. covalent bonded materials

Hint:

Polar materials = molecules with a permanent dipole moment due to an uneven distribution of charges.

Answer 1

The Correct Option is A

Step 1: Definition of a dipole moment.
A dipole moment arises when there is a separation of positive and negative charge centers in a molecule.
Step 2: Polar vs Non-polar.
- Polar materials have a permanent dipole moment due to asymmetric charge distribution (e.g., \( \text{H}_2\text{O} \)).
- Non-polar materials have no permanent dipole moment, where the centers of positive and negative charges coincide (e.g., \( \text{O}_2 \)).
Step 3: Conclusion.
Molecules with a permanent dipole moment are called polar materials.
Final Answer: \[ \boxed{\text{polar materials}} \]