The video explains the properties and uses of hydrogels, focusing on their super absorbent nature. It begins with an introduction to hydrogels found in disposable nappies, followed by an experiment demonstrating their ability to absorb water and react to salt. The chemical structure and reactions of hydrogels are discussed, highlighting how they maintain dryness by interacting with water. The video concludes with industrial applications, such as their use in contact lenses, emphasizing their flexibility and comfort.

What is the primary function of hydrogels in disposable nappies?

• To provide fragrance

• To add color

• To absorb and retain moisture

• To increase weight

During the experiment, what happens to the hydrogel when salt is added?

• It expands further

• It shrinks back to its original size

• It becomes sticky

• It changes color

What causes the polymer chains in hydrogels to unwind when they come into contact with water?

• The loss of positive hydrogen ions

• The presence of salt

• The presence of air

• The addition of heat

How do sodium ions affect the hydrogel when salt is added?

• They cause the hydrogel to expand

• They neutralize the charges on the hydrogel

• They make the hydrogel more colorful

• They increase the hydrogel's temperature

What is the role of hydrogels in contact lenses?

• To retain water and maintain flexibility

• To provide color

• To increase weight

• To add fragrance