Final answer:
The equation ax by → bx ay exemplifies a double replacement reaction where components of two compounds exchange to form two new compounds. This is distinguished from single replacement reactions, where one element replaces another in a compound.
Step-by-step explanation:
The given chemical equation ax by → bx ay represents a double replacement reaction. In this reaction, the positive and negative parts of two compounds (ax and by) exchange places to form two new compounds (bx and ay). This kind of reaction commonly occurs between ionic compounds in aqueous solutions. It's important to note that for a double replacement reaction to occur, typically one of the products must be insoluble, forming a precipitate, a gas, or sometimes a molecular compound like water.
In contrast, a single replacement reaction involves one element substituting for another in a compound; for example, A + BC → AC + B. This is not the type we see here because only the cations or the anions are exchanged, but not both.