Question

What is meant by activity series of metals? State which of the following reactions will take place giving the suitable reason for each.

$\mathrm{Fe}\left(\mathrm{s}\right)+\mathrm{ZnSO}{}_4(\mathrm{aq})\to \mathrm{FeSO}{}_4(\mathrm{aq})+\mathrm{Zn}\left(\mathrm{s}\right)$

Answer 1

1. Activity series of metals

Elements are arranged on the basis of decreasing order of reactivity.

$\mathrm{K}>\mathrm{Na}>\mathrm{Ca}>\mathrm{Mg}>\mathrm{Al}>\mathrm{Zn}>\mathrm{Fe}>\mathrm{Ni}>\mathrm{Sn}>\mathrm{Pb}>\mathrm{H}>\mathrm{Cu}>\mathrm{Hg}>\mathrm{Ag}>\mathrm{Au}>\mathrm{Pt}$

Here potassium is a highly reactive metal and platinum is the least reactive metal.

2. Reaction

$\mathrm{Fe}\left(\mathrm{s}\right)+\mathrm{ZnSO}{}_4(\mathrm{aq})\to \mathrm{FeSO}{}_4(\mathrm{aq})+\mathrm{Zn}\left(\mathrm{s}\right)$

(Iron) (Zinc sulphate) (Iron sulphate) (Zinc)

3. Reason

As we can see from the activity series zinc is more reactive than iron so this is why iron cannot displace zinc from zinc sulphate solution.

This will not show a displacement reaction.

Displacement reaction: Reaction in which more reactive metal displaces less reactive metal from its aqueous solution.

So, this reaction will not take place.