Answer:
when 2 elements are switched out with each other when you look at the reactants and see the products u see that in total, 2 elements are switched out with each other. If that makes sense haha
Step-by-step explanation:
for example BaS+PtF2 —> BaF2+PtS
We can see in this example that on the left side (reactant) the S is with the Ba and when you look on the right side we see that S is on Pt instead of Ba. The same with F. F on the left was with Pt now looking at the right side it’s with Ba. That’s double replacement because 2 elements have been replaced. I hope this helps. Gl.