Which one of the following is a lyophilic colloid?

• (A) Gelatin
• (B) sulphur
• (C) Gold
• (D) Carbon

To determine which of the options is a lyophilic colloid, let's first clarify what a lyophilic colloid is. Lyophilic colloids, also known as "solvent-loving" colloids, have a strong affinity for the solvent in which they are dispersed. This means they can easily form stable colloidal solutions when mixed with a solvent, often resulting in a homogeneous mixture. Now, let's analyze the options provided:

Understanding the Options

• Gelatin: This is a protein derived from collagen, and it readily dissolves in water, forming a stable colloidal solution. Gelatin is indeed a classic example of a lyophilic colloid.
• Sulphur: This is a non-polar substance that does not have a strong affinity for water. It does not form stable colloidal solutions in water, making it not a lyophilic colloid.
• Gold: While gold can form colloidal solutions (like colloidal gold), it is considered a lyophobic colloid, meaning it does not have a strong affinity for the solvent and tends to be less stable.
• Carbon: Similar to sulphur, carbon in its elemental form does not dissolve well in water and does not form stable colloidal solutions, categorizing it as a lyophobic colloid as well.

Identifying the Correct Answer

From this analysis, it is clear that the only option that fits the definition of a lyophilic colloid is Gelatin (Option A). Gelatin's ability to dissolve in water and form a stable colloidal solution exemplifies the characteristics of lyophilic colloids.

Real-World Applications

Lyophilic colloids like gelatin are widely used in various industries. For instance, in the food industry, gelatin is used as a gelling agent in desserts, jellies, and marshmallows. In pharmaceuticals, it serves as a stabilizer in drug formulations. Understanding the properties of lyophilic colloids helps in utilizing them effectively in these applications.

In summary, when considering the options given, gelatin stands out as the lyophilic colloid due to its strong affinity for water and ability to form stable colloidal solutions. This characteristic is crucial in both scientific and practical contexts.