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The Reactivity Series

Metal Displacement Reactions.

A metal will displace (take the place of) a less reactive metal
in a metal salt solution.
This is similar to the non-metal displacement reactions
seen on page 23 of  the periodic table.

For example,
iron    +    copper(II) sulfate  arrow    iron sulfate  + copper.
Fe(s)      +      CuSO4(aq)      arrow      FeSO4(aq)  +   Cu(s)

Copper(II) sulfate is blue, iron sulfate is colourless.
During the reaction the blue solution loses its colour
and the iron metal is seen to turn pink-brown
as the displaced copper becomes deposited on it.

If a less reactive metal is added to a metal salt solution
there will be no reaction - nothing will happen!
For example, iron is less reactive than magnesium.
iron + magnesium sulfate arrow  no reaction.

In these displacement reactions
the metals are competing for the non-metal anion.
In the above examples the non-metal anion is sulfate - SO42-.
Reactions using chlorides or nitrates can also be used.
The order of the metals in the reactivity series
can be worked out by using these type of reactions.

For example,
tin would be seen to displace lead from lead chloride
but would not react with iron(II) chloride.

tin   +   lead chloride  arrow       tin chloride lead.
Sn(s)   +   PbCl2(aq)    arrow        SnCl2(aq)   +   Pb(s)

tin  +  iron(II) chloride  arrow      no reaction.
Sn(s)    +     FeCl2(aq)   arrow                        
Therefore tin must be above lead but below iron
in the reactivity series.

Copper would be seen to displace silver from silver nitrate
but would not react with lead nitrate.

copper  +  silver nitrate     arrow     copper nitrate silver.
Cu(s)   +   2AgNO3(aq)       arrow   Cu(NO3)2(aq)   +   2Ag(s)

copper  +  lead nitrate      arrow    no reaction.
Cu(s)    +    Pb(NO3)2(aq)  arrow                     
copper must be above silver but below lead
in the reactivity series.

These reactions can be written as ionic equations.

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