Which best describes gels?

Which best describes gels?

• A. A crystalline solid with uniform composition.
• B. A colloid where a solid is dispersed in a liquid.
• C. A suspension of solid in gas.
• D. Colloids consisting of liquids spread throughout a solid, such as jelly.

Answer: (D)

Gels are colloidal systems in which a liquid is immobilized by a three‑dimensional solid network, giving a soft, jelly‑like material. Jelly is a classic example: a gelatinous network traps water, so the liquid is spread throughout a solid matrix. This makes gels distinct from a crystalline solid, which has a uniform, repeating structure and is not gel-like. It’s also different from a sol, where solid particles are dispersed in a liquid, rather than a liquid held in a solid framework. And it isn’t a suspension of solid in gas, which would be a different kind of aerosol. The idea that best describes gels is a colloid in which liquids are spread throughout a solid, such as jelly.

Gels are colloidal systems in which a liquid is immobilized by a three‑dimensional solid network, giving a soft, jelly‑like material. Jelly is a classic example: a gelatinous network traps water, so the liquid is spread throughout a solid matrix. This makes gels distinct from a crystalline solid, which has a uniform, repeating structure and is not gel-like. It’s also different from a sol, where solid particles are dispersed in a liquid, rather than a liquid held in a solid framework. And it isn’t a suspension of solid in gas, which would be a different kind of aerosol. The idea that best describes gels is a colloid in which liquids are spread throughout a solid, such as jelly.