Which of the following will not form a colloidal system ?

Options

A. Solid-gas
B. Liquid-gas
C. Gas-gas
D. Gas-liquid

Explanation

To determine which of the following options will not form a colloidal system, we need to analyze each option:

1. **Solid-Gas**: This combination can form a colloidal system known as an aerosol. An example of this is smoke, which consists of solid particles dispersed in a gas.

2. **Liquid-Gas**: This combination can also form a colloidal system, which is another type of aerosol. Examples include fog and mist, where tiny droplets of liquid are dispersed in air.

3. **Gas-Gas**: This combination does not form a colloidal system; instead, it forms a perfect solution. Gases like nitrogen (N2) and oxygen (O2) mix completely without forming any colloidal particles.

4. **Gas-Liquid**: This combination can form a colloidal system. An example is soap lather, where gas bubbles are dispersed in a liquid.

Based on the analysis, the option that does not form a colloidal system is:

**Answer: Gas-Gas (Option C)**