1. COMMON REDOX REACTIONS

2. 5.2 SOME COMMON REDOX REACTIONS

4. Reaction of (left to right)
lithium with water, calcium
with water, zinc with
sulfuric acid, magnesium
with hydrochloric acid

5. These reactions are called displacement reactions
These reactions are called displacement reactions. Common reactive metals,
Mg, Al, Zn, Fe, will displace both copper and silver from solutions of their
ions and copper will displace silver. The more reactive metals, sodium, lithium,
calcium and barium, cannot be used in such displacement reactions because
they would react with the water of the aqueous solution (part (b) above).

6. Two displacement
reactions: (a) a granule
of zinc dropped into a
copper sulfate solution;
(b) copper wire dipped
into a silver nitrate
solution. For each case
the left-hand test tube
shows the metal just after
being dropped into the
solution: in the right-hand
test tube the metal has
been in the solution for
ten to twenty minutes

7. In these reactions the negative bromide and iodide ions lose electrons to form
the neutral bromine and iodine molecules; hence the bromide and iodide are
oxidised. The neutral molecules, chlorine and bromine, gain electrons (that is,
get reduced) to form the negative chloride and bromide ions.
The reverses of these reactions are not possible: bromine cannot oxidise
chloride; iodine cannot oxidise chloride or bromide.
Fluorine has been omitted from this discussion because it is so reactive that
it oxidises water to oxygen and thus cannot be used in the type of aqueous
halogen–halide reactions described here.