Question

Smoke is a colloid of:

• A. Solid in solid
• B. Liquid in solid
• C. Solid in liquid
• D. Solid in gas

Hint:

In smoke, small solid particles are suspended in the air, which is why it is classified as a solid in gas colloid.

Answer 1

The Correct Option is D

Smoke is a colloid of: 

• Option 1: Solid in solid - This refers to a solid dispersion in another solid, such as alloys. This is not the correct answer for smoke.
• Option 2: Liquid in solid - This refers to a liquid dispersed in a solid matrix, like some types of gels. This is not the correct answer for smoke.
• Option 3: Solid in liquid - This describes a suspension, where solid particles are dispersed in a liquid. This is not applicable to smoke.
• Option 4: Solid in gas - This is the correct answer. Smoke consists of fine solid particles (like soot) dispersed in a gas, which is what makes it a colloidal solution of solid in gas.

Explanation:

Smoke is a colloidal solution where solid particles (such as soot) are dispersed in a gas (air). This is why it is categorized as a solid in gas colloid.

Answer 2

Smoke is being classified by its physical state combination. Check each option against what smoke is actually made of.

1. Solid in solid: this would need one solid embedded in another solid, unrelated to smoke rising and dispersing freely through the air.
2. Liquid in solid: this would need liquid trapped in a solid network, which does not describe smoke drifting and spreading through air at all.
3. Solid in liquid: this would describe solid particles floating in a liquid, like a suspension, not particles floating through open air.
4. Solid in gas: smoke is made of tiny solid soot and ash particles carried along by the surrounding air. That is solid particles dispersed in a gas, matching smoke exactly.

Smoke's fine soot particles float and drift through air, which is a gas, so smoke fits solid dispersed in gas.

So the correct answer is solid in gas.