Question

A gel toothpaste is a mixture of a :

• A. liquid in a solid
• B. solid in a gas
• C. liquid in liquid
• D. gas in solid

Hint:

Gels are "jelly-like." They feel wet (due to the liquid) but hold their shape (due to the solid network). Think of it this way:
Dispersed phase (what's spread out) = Liquid
Dispersion medium (what it's spread in) = Solid This makes a gel a "liquid in a solid" colloid.

Answer 1

The Correct Option is A

Concept: Gels are a type of colloid. A colloid is a mixture in which one substance of microscopically dispersed insoluble particles is suspended throughout another substance. The type of colloid is defined by the phases of the dispersed substance and the dispersion medium. Step 1: Understanding what a gel is A gel is a colloidal system in which a liquid (the dispersed phase) is dispersed throughout a solid continuous network (the dispersion medium). The solid network gives the gel its structure and semi-solid, jelly-like consistency, trapping the liquid within it. Step 2: Analyzing the options for colloidal systems
(1) liquid in a solid: This describes a gel. The liquid particles are dispersed in a solid medium. Examples: gelatin, jelly, cheese, butter, gel toothpaste.
(2) solid in a gas: This describes a solid aerosol. Examples: smoke, dust in the air.
(3) liquid in liquid: This describes an emulsion. Examples: milk, mayonnaise.
(4) gas in solid: This describes a solid foam or solid sol. Examples: pumice stone, styrofoam, bread. Step 3: Applying to gel toothpaste Gel toothpaste has a characteristic jelly-like, semi-solid texture. This structure is formed by a solid network (gelling agents like hydrated silica or polymers) that entraps liquid components (like water, sorbitol, glycerin). Therefore, a gel toothpaste is a system where a liquid is dispersed in a solid.