2.23 explain the uses of carbon dioxide in carbonating drinks and in fire extinguishers, in terms of its solubility and density

The stuff that makes your fizzy drinks fizzy is the carbon dioxide. As CO2 is slightly soluble in water and dissolves in drinks when user high pressure, a slightly acidic solutions forms due to the formation of carbonic acid. It eventually goes flat because, once you open the bottle, the CO2 is escaping (when it is flat, its all gone)

CO2 is more dense than air, this makes it perfect for fire extinguishers. The CO2 will sink onto flames and 'suffocate' them (stop the oxygen getting to the flames). As fire needs oxygen to burn, the fire will go out as no oxygen can get to it.

NOTE: CO2 fire extinguishers are only used when water extinguishers aren't safe. For example, when putting out an electrical fire.