Is a single replacement reaction takes place when a free metal is more active than a metal combined in a compound?

Yes, a single replacement reaction occurs when a free metal is more active than a metal in a compound. In this type of reaction, the more reactive metal displaces the less reactive metal from its compound, resulting in the formation of a new compound and the release of the less reactive metal. This principle is based on the reactivity series of metals, which ranks metals according to their ability to displace other metals from compounds.