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: Defining Dipole Moment.
A dipole moment occurs when positive and negative charge centers within a molecule are separated.
Step 2: Polarity.
- Polar substances possess a permanent dipole moment because of uneven charge distribution (e.g., \( \text{H}_2\text{O} \)).
- Non-polar substances lack a permanent dipole moment, as positive and negative charge centers align (e.g., \( \text{O}_2 \)).
Step 3: Summary.
Molecules exhibiting a permanent dipole moment are classified as polar substances.
Final Answer: \[ \boxed{\text{polar materials}} \]