Question

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

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

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 highly reactive metal and platinum is least reactive metal.

2. Reaction

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

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

3. Reason

As we can see from activity series zinc is more reactive than iron so zinc can displace iron from iron sulphate solution.

This is displacement reaction.

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

So, this reaction will take place.