Oxidation: A reaction that
occurs when a substance gains oxygen.
Oxidizing agent: The
substance that oxidizes other reacting substances in a reaction while it is
being reduced.
Reduction: The reaction that
occurs when a substances loses oxygen.
Reducing agent: The
substance that reduces other reacting substances in a reaction in a reaction
while it is being oxidized.
Redox reaction: A chemical
reaction in which oxidation and reduction occur simultaneously.
Metal displacement reaction:
A reaction where a more electropositive metal replaces a less electropositive
metal from its salt solution. In a metal displacement reaction, a more
electropositive metal acts as the reducing agent whereas the ion of the less
electropositive metal in the salt solution acts as the oxidizing agent.
Halogen displacement
reaction: A reaction where a more reaction halogen replaces a less reactive
halogen from its halide solution. In a halogen displacement reaction, a more
reactive halogen acts as the oxidizing agent whereas the halide ion of the less
reactive halogen acts as the reducing agent.
Rusting of iron = the
corrosion of ion. Rusting can be
prevented when iron is in contact with a more electropositive metal. Rusting
occurs faster when iron is in contact with a less electropositive metal.
Reactivity series of metals:
A list of metal that are arranged according to their reactivity with oxygen.
The descending order of reactivity of metal with oxygen is magnesium, zinc,
iron, lead and copper.
Carbon is placed between
aluminium and zinc in the reactivity series. Magnesium is placed higher than
carbon in the reactivity series. Carbon acted as a reducing agent because the
metal oxide was reduced to metal in the presence of carbon.
Hydrogen is placed between
zinc and iron in the reactivity series. Hydrogen gas acted as a reducing agent
because the metal oxide was reduced to metal in the presence of hydrogen gas.
In an electrolytic cell,
oxidation takes place at the anode whereas reduction takes place at the
cathode.
In a chemical cell,
oxidation takes place at the negative terminal (anode) whereas reduction takes place at the positive terminal (cathode).
