Chemical Effects of Electric Current, Class 8 Science Video Lecture

introduction all matter is made of atoms
protons and neutrons occupy the center
portion of the atom and the electrons
revolve around them in a particular
orbit electrons which are in the
outermost orbit are responsible for
conduction of current electrons flow
from a body or point where there is an
excess of electrons to a body or point
where there is a deficit of electrons in
other words electrons flow from a body
that is negatively charged to a body
that is positively charged
objectives at the end of this lesson
you'll be able to explain the structure
of atoms define conductors and
insulators understand the electrical
conductivity of some liquids in general
identify the chemical effects of
electric current list the uses of
chemical effect such as electroplating
we classify the materials as conductors
and non-conductors materials which allow
electric current to pass through them
are good conductors of electricity
metals like copper aluminum a few
examples of it materials which do not
allow electric current to pass through
them easily are called
as poor conductors of electricity
materials such as rubber and plastic are
the example of this we use tester to
test the conductivity of materials which
are in solid state
do liquids can
electricity most liquids that conduct
electricity are solutions of acids bases
and salts chemical effect and
electrolysis when electric current is
passed through acidified water water
molecules split into hydrogen and oxygen
the two metal rods shown in the diagram
are called electrodes this type of
effect produced by electricity is called
the chemical effect and the process is
termed as electrolysis can we use pure
water in the place of acidified water
find out
electroplating it is common practice to
coat articles made of cheap metals such
as iron or steel with a thin layer of
less reactive metal a steel object for
example a spoon is connected to the
negative terminal of current source the
positive terminal is connected to the
bar of the metal for example pure silver
thus the spoon acts as the cathode in
the electrolysis while the bar of the
metal acts the anode the electrolyte is
a solution of salt that contains the ion
of the anode metal for example silver
nitrate as soon as electric currents
start flowing through the solution
electrons begin to escape from the
silver an old this result in the
formation of positively charged ions
which separate from the anode and pass
into the solution there they migrate
towards the cathode attracted by its
negative charge when they reach the
cathode they accept electrons from it
and change into silver atoms which
deposits onto the cathode in the form of
thin metallic layer the thickness of the
layer depends on the conditions under
which the electrolysis is conducted this
process is known as electroplating
use of chemical effect for silver and
gold plating this type of plating is
done to deposit a thin layer of gold or
silver on surface of the other metal
most often copper it gives a gold or
silver finish to the artificial jewelry
and ornaments silver plated articles
gold plated articles
did you know electroplating is widely
used in industry for coating metal
objects with a thin layer of a different
metal for example chromium plating is
done on many objects such as car parts
bath taps kitchen gas burners bicycle
handlebars wheel rims and many others
tin cans used for storing food are made
by electroplating tin into iron thus
food does not come into contact with
iron and is protected from getting
spoiled iron is used in bridges and
automobiles to provide strength however
I intend to corrode and rust so a
coating of zinc is deposited on iron to
protect it from corrosion and rusting
chemical effects of electric current the
passing of electric current through
liquids or conducting solutions causes
chemical reaction more importantly
chemical activity may occur in the
liquids around the electrodes bubbles of
gas are formed deposits of metal may be
seen and changes of color may occur on
the electrodes this reaction depends on
what liquids and electrodes are used the
passing of electric current through a
liquid causes chemical changes this
process is known as electrolysis
summary let us summarize what we have
learned some liquids are good conductors
of electricity and some are poor
conductors most liquids that conduct
electricity are solutions of acids bases
and salts the passage of an electric
current through a conducting liquid
causes chemical reactions the resulting
effects are called chemical effects of
currents the process of depositing a
layer of any desired metal another
material by means of electricity is
called electroplating