The work alternate can be an adjective, transitive verb, or a noun. When used in the form of an adjective, it means something that is occurring in or forming a repeating pattern or something that happens every other time. When alternate is used as a verb, it means to do different things so that one follows the repeating process.
The word equivalent can be used as an adjective. It means possessing the same value or meaning. Equivalent is a better word to use since it only has that singular meaning. Equivalent is used to explain that something is the same as something else.