Which one of the following colloidal systems is represented by soda water?

The correct answer is Option B: Gas in liquid.

Here's why:

* A colloidal system is a mixture where one substance is dispersed evenly throughout another.

* Soda water is essentially carbon dioxide gas (CO₂) dissolved in water (a liquid).

* Therefore, soda water represents a gas (CO₂) dispersed in a liquid (water).

Let's look at why the other options are incorrect:

* Option A: Liquid in gas This would be something like fog or mist, where tiny liquid droplets are suspended in air (a gas).

* Option C: Solid in gas This would be something like smoke, where tiny solid particles are suspended in air.

* Option D: Liquid in liquid This would be an emulsion, like milk, where tiny droplets of one liquid are dispersed in another liquid.

So, to remember: Soda water = Gas (Carbon Dioxide) in Liquid (Water).