Potassium is more reactive than aluminium, so no reaction takes place. But aluminium is more reactive than copper, so it replaces the copper in copper nitrate
<h3>Explanation:</h3>
More reactive metal compound + less reactive metal
-> no reaction
However
Less reactive metal compound + more reactive metal
-> more reactive metal compound + less reactive metal
This is called substitution reaction where the more reactive metal replaces the less reactive metal in the compound.
