Are solutions always of liquids

Answer 1

I believe when the average person thinks of a solution, they are imagining a solid dissolved in a liquid, and this may be the most common type of solution. However, there are at least six additional types of solutions: 1) A liquid dissolved in one or more other liquids, for example acetic acid in water (vinegar), ethyl alcohol in water (vodka), or hexane dissolved in toluene; 2) A liquid dissolved in a solid as in Mercury dissolved in silver (silver amalgam) or cesium dissolved in potassium provided the temperature is above 83.3 deg. F. (Cesium melts at 83.3 deg. F.); 3) One gas dissolved in one or more gasses for example oxygen, carbon dioxide, and argon dissolved in nitrogen (air); 4) One or more solids dissolved in another solid, as in steel, which is a solution of carbon in iron, although modern carbon steels contains small amounts of other solid elements also dissolved in iron; 5) One or more gasses dissolved in a liquid such as carbon dioxide dissolved in water, which is "soda" or "sparkling water," or boron trifluoride dissolved in diethyl ether; 6) A gas dissolved in a solid. This one is tough, and the only examples I know offhand are solutions of hydrogen gas in certain metals and nitrogen dissolved in ice. Hydrogen is quite soluble in nickle and in many other transition metals including iron and copper. It is also soluble in several of the noble metals (rhodium, palladium, and gold). I would be very surprised if there aren't other gasses that dissolve in solids. A search using one of the internet search engines would probably yield some other examples.