* Mixture: A mixture is a combination of substances where each substance retains its own properties. The substances in a mixture can be easily separated.

* Solution: A solution is a homogeneous mixture where one substance (the solute) is dissolved evenly throughout another substance (the solvent).

In soda water:

* Solute: Carbon dioxide gas (CO2)

* Solvent: Water (H2O)

The CO2 dissolves in the water, forming carbonic acid (H2CO3), which gives soda water its characteristic fizz. This is a homogeneous mixture, meaning the CO2 is evenly distributed throughout the water. You can't easily separate the CO2 from the water just by letting it settle like you could with some mixtures.

Therefore, soda water is considered a solution.