Which of the following best represent solid gas mixture?

Analysis

The question asks us to identify a mixture where a solid substance is dispersed within a gaseous medium (a solid-in-gas colloid).

Concept Explanation

In chemistry, mixtures where one substance is dispersed throughout another are called colloids. Colloids are classified based on the physical state of the dispersed phase (the substance being spread) and the dispersion medium (the substance it is spread into).

• Solid-in-gas colloid: This occurs when solid particles are suspended in a gas. This is commonly referred to as an aerosol.
• Let's evaluate the options: • Milk: This is an emulsion (liquid dispersed in liquid). • Kerosene: This is a liquid mixture (a solution of hydrocarbons). • Soil: This is a complex mixture of solid particles, water, and air, but it is primarily a solid-solid or solid-liquid mixture. • Smoke: This consists of fine solid particles (soot/ash) suspended in air (a gas).

Step-by-Step Solution

1. Identify the components: We are looking for a "solid" dispersed in a "gas."
2. Evaluate Smoke: Smoke is produced by the incomplete combustion of fuels. The visible part of smoke is made up of tiny solid particles (carbon/soot) that are carried by the hot gases produced during combustion.
3. Match with the definition: Since smoke is a collection of solid particles floating in a gas, it perfectly fits the definition of a solid-gas mixture (aerosol).
4. Verify against other options: None of the other options represent a solid dispersed in a gas.

Conclusion

Exam Tip

When dealing with colloid questions in JAMB, remember this simple table:

• Smoke: Solid in Gas
• Fog/Mist: Liquid in Gas
• Milk/Mayonnaise: Liquid in Liquid (Emulsion)
• Foam: Gas in Liquid