Arrange the metals used in this experiment (including H2 and Ag) in order of decreasing reactivity (most reactive metal first). The metals to be included are Ag, Al, Ca, Cu, Fe, H2, Mg, Na, Pb, Sn, and Zn.

Explanation:

According to the reactivity series chart, elements from high to lower reactivity are arranged as follows.

    K, Na, Ca, Mg, Al, C, Zn, Fe, Sn, Pb, H, Cu, Ag, Au

So, using this standard reactivity chart of metals we will place the given metals in the order of decreasing reactivity as follows.

     Na > Ca > Mg > Al > Zn > Fe > Sn > Pb > > Cu > Ag