Final answer:
The reaction between aluminum and copper nitrate is a single-replacement reaction. Aluminum does not react with potassium nitrate due to the reactivity series, where aluminum can replace less reactive metals like copper but cannot replace more reactive metals like potassium.
Step-by-step explanation:
The type of chemical reaction that occurs when aluminum (Al) reacts with copper nitrate (Cu(NO3)2) is known as a single-replacement reaction. In this reaction, aluminum replaces copper from its compound forming aluminum nitrate and copper metal is released.
Aluminum does not react with potassium nitrate (KNO3) although it reacts with copper nitrate because of the reactivity series of metals. In the reactivity series, aluminum is above copper but below potassium, meaning it can replace copper from its compounds but not potassium. Aluminum is more reactive than copper, which is why the reaction with copper nitrate occurs, while potassium being more reactive than aluminum prevents any reaction with potassium nitrate.