A solution is a homogeneous mixture of two or more substances.
There are many types of solutions.
Gas in Gas
• Air — oxygen and other gases dissolved in nitrogen.
Gas in Liquid
• Fish tank — oxygen in water.
• Carbonated beverages — carbon dioxide in water.
• Blood — oxygen and carbon dioxide are essential components of blood chemistry.
Liquid in Liquid
• Windshield washer fluid — methanol in water.
• Alcoholic beverages — ethanol and other solutes in water.
• Vinegar — acetic acid in water.
Solid in Liquid
• Maple syrup — sugar in water
• Brine — salt in water.
• Body fluids — complex aqueous solutions of sugar, urea, electrolytes, and many other solutes.
Gas in Solid
• Hydrogen dissolves rather well in palladium and tin.
Liquid in Solid
• Dental amalgam — mercury in silver, tin, and copper.
• Hexane in paraffin wax
Solid in Solid
• Steel — carbon atoms in a crystalline matrix of iron atoms.
• Bronze — copper and tin.
• Brass — copper and zinc.