Applications of redox reactions in Combustion, Metallurgy, Respiration, Rusting, Bleaching, Batteries, Corrosion

1. Standard/ Class/ Grade XI Chemistry
Chapter 5 Redox Reactions
Gurudatta Wagh
Applications of Redox Reactions
1) Combustion: Burning of a substance by oxidation with oxygen in air
Methane burns by oxidation with oxygen. The oxidation number of
carbon increases from -4 to +4 and that of oxygen decreases from 0 to
-2. Hence it is a redox reaction. Methane is a reducing agent and
oxygen is an oxidizing agent.

2. 2) Bleaching = Removing of colour or
decolourization
The chemicals used as oxidizing agents are a)
sodium hypochlorite NaOCl to remove stains;
b) chlorine in making white paper, and c)
hydrogen peroxide H2O2 for bleaching dark
hair.
3) Batteries: In Daniel cell
electrons are transferred from zinc
to copper. Zinc is oxidized by
transferring two electrons to Cu2+
ions which get reduced. Oxidation
number of zinc increases from 0 to
+2 and that of copper decreases
from +2 to 0.

3. 4) Metallurgy: Zinc sulphide is converted to
zinc oxide by roasting. Oxidation number of
sulphur increases from -2 to +4 and that of
oxygen decreases from 0 to -2. Zinc oxide is
reduced by coke to make zinc. Oxidation
number of zinc decreases from +2 to 0 and
that of C increases from 0 to +2.
6) Corrosion: Rusting of iron
5) Respiration: Glucose reacts with
oxygen to give CO2 and H2O and
energy is released. Oxidation
number of carbon increases from 0
to +4 and that of oxygen decreases
from 0 to -2.