Answer:
Ni (s) is oxidized because it loses electrons. This makes it the reducing agent.
CuCl₂ (aq) is reduced because it gains electrons. This makes it the oxidizing agent.
Step-by-step explanation:
In the reaction:
Ni(s) + CuCl₂(aq) → Cu(s) + NiCl₂(aq)
Ni (s) is oxidized because it loses electrons. This makes it the reducing agent.
------------> Ni (s) has an oxidation number of 0. All lone atoms (that are not ions) have a 0 oxidation number.
-------------> In NiCl₂ (aq), chlorine must have an oxidation number of -1, and because there are two chorine atoms, they contribute a total -2 charge. To make the overall charge neutral, nickel must have an oxidation number of +2 to balance the charges.
--------------> Because nickel goes from an oxidation number of 0 to +2, this indicates that it lost electrons and was reduced.
CuCl₂ (aq) is reduced because it gains electrons. This makes it the oxidizing agent.
-------------> In CuCl₂ (aq), chlorine must have an oxidation number of -1, and because there are two chorine atoms, they contribute a total -2 charge. To make the overall charge neutral, copper must have an oxidation number of +2 to balance the charges.
------------> Cu (s) has an oxidation number of 0. All lone atoms (that are not ions) have a 0 oxidation number.
--------------> Because copper goes from an oxidation number of +2 to 0, this indicates that it gained electrons and was oxidized.