Final answer:
The reaction Mg + CuCl2 = MgCl2 + Cu is a metal replacement reaction, a subcategory of single-replacement reactions, where a more reactive metal (magnesium) replaces a less reactive one (copper).
Step-by-step explanation:
The reaction shown, Mg + CuCl2 = MgCl2 + Cu, is an example of a metal replacement reaction, which is a type of single-replacement reaction. In this reaction, a more reactive metal (magnesium) displaces a less reactive metal (copper) from its compound. Consequently, magnesium bonds with chlorine to form magnesium chloride (MgCl2), while copper metal is released as a solid.
The concept of a metal replacement reaction can be further understood by considering that magnesium, having a higher reactivity than copper, loses two electrons to form Mg2+ ions while each chlorine atom gains one electron to form Cl- ions. The reaction involves not only the replacement of the metal but also the transfer of electrons between atoms, a process known as oxidation and reduction. Here, magnesium is oxidized, and chlorine is reduced. The reaction is also an example of a redox reaction.
The type of reaction shown above is a single-replacement reaction. Specifically, it is a metal replacement reaction because a more reactive metal, magnesium (Mg), is replacing a less reactive metal, copper (Cu). The balanced equation for the reaction is:
Mg(s) + CuCl2(aq) → MgCl2(aq) + Cu(s)
In this reaction, the magnesium atoms lose two electrons and are oxidized to form Mg2+ ions, while the copper ions gain two electrons and are reduced to form solid copper metal. This reaction involves the transfer of electrons between the metal atoms.